It is one thing to understand what advantages an animal such as ourselves gains by being able to exploit spectral information in its environment, but quite another to understand how the animal benefits by having conscious color experiences. Since experiences are private, how could they confer a selective advantage? Could they do so by enabling voluntary action of a sort forever beyond the resources of the most ingeniously designed wavelength-processing robot? Or is there an ancient biological link between color experience and the emotions that colors evoke in us?
Color vision is inseparable from spatial vision. Chromatic and achromatic aspects of visual experience together subserve our perception of the forms of objects. This view is supported by physiological studies demonstrating that both color and luminance are carried along with form information on the same optic nerve fibers, albeit at different spatial scales. These scale differences can be summarized by contrast sensitivity functions measured with chromatic and achromatic spatial sinusoids, and may be illustrated by digitally filtered images that separate achromatic and chromatic variations. Analyses of the chromatic content of natural images also demonstrate a close link with the chromatic and spatial tuning of neural pathways. While characteristic properties of natural scenes can predict general characteristics of visual coding, color can vary widely across individual images, and thus could not be represented optimally by a fixed visual system. However, color coding is not fixed, but rather adjusts to both the average color and distribution of colors in scenes through processes of adaptation. Such adjustments may support color constancy and coding efficiency, and may also optimize detection and discrimination of colors that are novel in an image. Finally, the spatial properties of color-coding mechanisms are essential to our perception of figure and ground. Chromatic (border) contrast enhances the difference between figure and ground, while homogenization of object surfaces is facilitated by short- and long-range processes of assimilation and color spreading.
Color is a visible aspect of objects and lights, and as such is an objective characteristic of our phenomenal world. Correspondingly also objects and lights are objective, although their subjectivity cannot be disregarded since they belong to our phenomenal world. The distinction between perception and sensation deals with colors seen either in complex displays or in isolation. Reality of colors is apparently challenged by virtual reality, while virtual reality is a good example of what colors are. It seems difficult to combine that aspect of reality colors have in our experience and the concept that colors represent something in the external environment: the distinction between stimulation and perceived object is crucial for understanding the relationships between phenomenal world and physical reality. A modern concept of isomorphism seems useful in interpreting the role of colors. The relationship between the psychological structure of colors and the physical stimulation is enlightened by the analysis of pseudocolors. The perceptual, subjective characteristics of colors go along with the subjectivity of scientific concepts. Colors, emotions, and concepts are all in some people's mind: none of them is independent of the subject mind. Nevertheless they can be communicated from person to person by an appropriate scientific terminology.
This article comments on the current interest in the subject of consciousness and the related subject of the nature of color experiences. Color is seen to be a special symbolic language into which spectral power distributions of areas of the visual field, arriving at the retina and related to those of other areas, are translated. With a code of five 'letters,' Y, R, B, G and Gray and modulation of these towards dark and light the information content of an unlimited number of spectral power distributions is efficiently conveyed to consciousness. The philosophical conundrum of 'inverted spectra' is briefly addressed, as is the difference in focal and unique green and the reappearance of red at the short wave end of the spectrum.
Panelists' completed papers were circulated a few weeks before the Congress. This was so that all could have some
early understanding of each other's points of view and so be well prepared for discussion during the symposium. In the
event the debate began almost immediately by e-mail.
Evidence presented supports the linguistic relativity of color categories in three different paradigms. Firstly, a series of cross-cultural investigations, which had set out to replicate the seminal work of Rosch Heider with the Dani of New Guinea, failed to find evidence of a set of universal color categories. Instead, we found evidence of linguistic relativity in both populations tested. Neither participants from a Melanesian hunter-gatherer culture, nor those from an African pastoral tribe, whose languages both contain five color terms, showed a cognitive organization of color resembling that of English speakers. Further, Melanesian participants showed evidence of Categorical Perception, but only at their linguistic category boundaries. Secondly, in native English speakers verbal interference was found to selectively remove the defining features of Categorical Perception. Under verbal interference, the greater accuracy normally observed for cross-category judgements compared to within-category judgements disappeared. While both visual and verbal codes may be employed in the recognition memory of colors, participants only make use of verbal coding when demonstrating Categorical Perception. Thirdly, in a brain- damaged patient suffering from a naming disorder, the loss of labels radically impaired his ability to categorize colors. We conclude that language affects both the perception of and memory for colors.
The visual world, the world we see, is a world populated by colored objects. Central to any adequate theoretical account of color is a theory of how these colors are experienced. The best theory of color experience, I have argued previously, is an Illusion theory: objects are represented in color experience as having colors that neither they nor any physical object actually has. We cannot, however, be content with this conclusion which comprises a negative thesis. We need to go on and ask how we should think of colors. For some purposes, e.g. for most practical purposes, the answer is that we should think of colors in the same way as we always did. For some purposes, e.g. theoretical and philosophical purposes, however, we need to develop a more comprehensive account. In principle, we should expect to develop a pluralist framework for colors, one that has room for a range of different, but related, colors.
The aim of this investigation is to describe the semantics of color in chromatism (from the ancient Greek triune notion of <<chroma>>: (1) color as ideal (Id- plan), psychic; (2) tint as physical, verbal; material (M- plan), physiological, syntonic (S-plan), and (3) emotion as their informative-energetic correlation). Being a new field of science, chromatism links humanitarian and natural subjects by means of interdiscipline investigation of a real (f-m) man living in a real (color) surrounding environment. According to the definition for <<chroma>>, color may be considered to be the most universal notion, permitting to assume the unity of both a man and an environment. Due to this assumption, we may give models of human intellect.
Margaret Walch, Director of the Color Association of the United States (CAUS) and writer on historic color palettes proposed that color functions to bring aesthetic values and delight into our lives. The aesthetic and commercial values of color go hand in hand affecting the marketplace. What is color in the 21st Century? Color will be clever and play tricks for us Ms. Walch responds. In her slide presentation, Ms. Walch discussed the colors the Association's Interior Forecasting Committee predicts will be popular in 2003, and she combined this with an examination of four palettes that related to these colors.
Ms. Stein, President and Creative Director of The Color Council took us through a fast paced international tour via slide presentations of the latest furnishings, fabrics, lighting, gifts and accessories for the home. She explained that color events and predictions occur simultaneously with no time lag in spreading color news throughout industries, perhaps due to technology and the Internet. She noted a global network for distinctive pockets of color wherein little difference of color exists between Europe and New York.
This paper takes into consideration the role of color as a non-verbal language between human beings and the environment. The communication is based on the function of the color vision to separate and identify. A language about color can be based on the same. The concept behind the Natural Color System is color differentiation and color identification, which I find very useful both in color education of design students and in environmental color design work. A commission to plan the exterior use of color for a whole mining town on 78 degree(s) North in Longyearbyen, Spitsbergen, will illustrate my ideas. This will serve as an example of how these different 'languages' can work together. After a twenty years ongoing process this work is now almost fulfilled and the result will be shown in the presentation.
Guidelines to publishing and transmitting color via the Internet. An introduction to how individuals can cope with color issues using off the shelf package solutions and a glimpse to what there is on the development frontier. Topics to be discussed include: (1) Optimizing your files for transfer via the net with an off the shelf software package. (2) Embedded color management packages in some off the shelf packages. (3) Mac and Window differences. (4) A look at compression pros and cons. (5) An introduction to some of the high end color calibration systems and equipment.
In this paper problems, aims, and preliminary results from an investigation of color appearance in north- and south- facing rooms are presented. This first part of the project includes an experimental study of six colors in two nuances of chromaticness, altogether twelve colors. Several methods for assessment and description have been used. Hue shifts are in focus together with chromaticness and room character. Color appearance was compared between rooms in different compass orientations and found to be clearly different. In the south facing room yellow colors tended towards elementary yellow, while greenish blue tended towards green. All colors increased in chromaticness. Colors in the north- facing room, on the other hand, tended to go in the opposite direction; greenish blue tended towards elementary blue and elementary blue increased its cromaticness most of all. Reddish blue colors showed no distinct tendency. Color variations due to reflexes, patches of light, shade and, shadow were important in assessing the identity color. The identity color is discussed together with the elasticity concept that has been developed to describe the range of different color appearances of an inherent color inside the room.
The building facade has a visually defined impact and there are numerous forces driving the choice of colors used. Commercial premises such as pubs, restaurants and bars are normally but not always clearly marked as such. Although we human beings can have the option of free choice in the colors we use around the home there are numerous positive driving forces dictating those we use in business life. Many of these factors have been identified. They depend on the type of population these venues serve, their geography and their traditions.
The quality of natural light, the landscape surrounds and the techniques of construction are important factors in the selection of architectural colors. Observation of exterior walls in differentiated climates allows the recognition of particularities in the use of color which satisfy the need for visual comfort. At a distance of 2000 kilometers along the coast of Peru, Lima and Mancora at 12° and 4° respectively, are well defined for their climatic characteristics: in Mancora sunlight causes high reflection, in Lima overcast sky and high humidity cause glare. The study of building color effects at these locations serves to illustrate that color values may be controlled in order to achieve visual comfort and contribute to color identity.
This paper is an invitation for international research cooperation in the field of color and architecture. It presents a thesis work starting from an experience shared by many architects and others who have at some time chosen facade colors: The house is not the color I thought it would be observations of painted timber and rendered facades showed consistent variation patterns for differences between the 'approximate perceived colors' and the inherent colors, involving both hue and nuance. These results were achieved in Swedish light conditions, nature and color traditions. Comparisons with similar surveys in other parts of the world could help the understanding of the found variation patterns and their causes.
While traditional/vernacular color scheme of a city in historical regions should be protected, changes in life style reflect on cityscapes in all ways, in which the role of new materials, paints, etc. cannot be denied. Lack of architectural and urban design studies in this field added to existing countless opportunities of new technology, with the strong desire to trying those by building owners, users and contractors have caused a chaotic situation in the use of color in cities; Bursa with its historical colorful background is no exception. All these form a trial and error phase, with painted or materials applied on surfaces without a sensitive touch to transform them to color. This must be taken in mind that color with its inherent power can bind past, present and future of the city and create an urban sense of place.
The two fundamental questions of this study are: (1) Do the concept of black and the color black evoke the same association? (2) Do all cultures (and all social groups) in fact rate the color black mainly negatively? The first part of our investigation deals with the color associations of a particular professional group within the (endemic) society of Austria, the second part with people who, by reason of their skin color and origins, have a very personal association with black. So far, 51 architects, designers and students of design have been questioned about their associations with black and other colors/color combinations (presented as a concept and as a color sample). No significant differences were found (similarly for the other elementary colors W, Y, R, B, G). By contrast, clear differences from the connotations of black reported in European literature were demonstrated by 40 (dark-skinned) persons (37 from various parts of Africa, 2 Caribbean and 1 Colombian), questioned about their associations with black, the term(s) used for black, the significance and the use of black within their culture or tribe, and about the significance of their own skin color, both to them personally and to their own culture.
This study concerning the use of color among architects and public in Finland during the post-war reconstruction period is part of my forthcoming doctoral thesis. Due to cultural comparison, the study shows that a unique silent agreement among public and professional tastes concerning color did exist. This is welcome feature in the way understanding the confusing situation between architecture and everyday life.
How important is color in the design of our built environment? Prototypes and massing models for designs are often presented in white or monochromatic combinations, irrespective of the materials incorporated and the colors that may be applied in the final constructed building, interior or object. Therefore, it is of interest to identify the way color is positioned by designers in how they go about the business of making environments. The built environment is understood by the designers and design researchers generally in one of four fields - as object, as product, as communicator, or as social domain. In addition, Franz identified four conceptions of designing held by designers - the experiential conception, the structural conception, the production conception and the retail conception. Fashion and style are often associated with color in a local context and may simply be applied to the physical environment because it is in fashion, rather than because of what it communicates more broadly. It is assumed that the integration of color in the built environment is influenced by these understandings. In order to address color's position in the design process and the importance of color in relation to space, form, and the experience of place, a selection of Queensland architects and interior designers were surveyed. The study is not conclusive, however, it does identify differences and commonalities between the participants that are of interest in light of the above issues. Explorations into environmental meaning, in addition to color theory and decorative applications, are hypothesized to be important sources of information for designers involved in the coloration of the built environment.
The experiments were carried out to confirm how the evaluation on an exterior color of building was influenced from the colors of the foreground buildings. Main results are as follows. Contrast acts on the evaluation of conspicuousness, and assimilation acts on the evaluation of harmony and the necessity of the restriction oppositely. As for striking building, it is not easy to harmonize with the surroundings and the necessity of the restriction is also high. The buildings stands out well, is not harmonized easily by the color difference with the foreground buildings large, and the necessity of the restriction rises further.
This project is about color-design paintings with evident chromatic contents to be located in several parts of the city. This project aims to make a two-dimension work alive in the three-dimension urban environment thus provoking a global vision of color and at the same time establishing a relation between both dimensions of the surrounding environment. Each work, which consists of a big colorful canvas, invites people to accept color as an active and aesthetic element to be experimented also in those areas that are normally without color. The project of color has been created and diversified considering the differences among various parts of the city. It is a confluence- comparison relationship between color and architecture. This project is part of a wide-research on 're-education to color,' helping people to enjoy the positive vital message of color. Re-appropriation of color is therefore an element of cultural evolution for a more harmonious and sensitive relationship with the environment. Hence, it is the responsibility of scientists and aesthetic operators to investigate and communicate new suggestions in the exciting field of color. Aesthetic operators along with scientists may contribute to a richer exploration in the use of color under innovative circumstances, in order to stimulate sensitivity to colors.
The urban shape is understood as the sensitive expression of an idea of city. The emergent aspects, at present involved in the development of technologies of information and communication, have modified the idea of city and, consequently, its shape, which expresses in its appearance the different aspects of this change. This is regarding the physical component, which is strongly engaged with its chromatic expression. As regards the human factor, the construction of the image is considered as a determining aspect of the process of knowledge, which is at present immersed in other dimensions of time and space where speed, simultaneity and alteration constitute parameters of new mechanisms of syntax and construction of the urban image. The challenge consists in interpreting how the urban shape expresses that idea of city and shows the changes in its appearance, in knowing how man builds his image considering this computerized era as well as discovering which the role of color is in this discussion.
Outdoor advertisements must be one of the major factors that affect our psychological impression for townscapes. They often conflict with propr color environments in cities particularly in historic cities like Kyoto. In this study we investigated how outdoor advertisements influenced our visual evaluation of townscapes in Kyoto. In recent years, a new regulation for outdoor advertisements came into operation in Kyoto and some of the advertisements have been replaced or removed gradually. We examined psychological evaluation for the townscapes before and after their changes. In the experiment, subjects evaluated 'visual harmony,' 'visual busyness,' 'visual comfort' and 'suitability to Kyoto' of townscapes projected on a screen. The results indicated that the evaluation of 'visual busyness' significantly decreased with the amount of the advertisements. The relations between the advertisements and the psychological evaluation of the townscape are discussed.
Author(s): Mika Takahashi; Kazumi Fujibayashi; Tomomi Shimonaka; Masako Sato; Kazuhiro Sawa
This is a case study for practical survey and assessment of urban landscapes containing outdoor advertisements in Osaka City, Japan. We practically surveyed and analyzed the colors used on the outdoor advertisements in the three urban areas: the business area long the main street, the amusement area along the shopping street, and the station plaza in front of the railroad terminal. Further by the laboratory experiments, we examined the interrelation between the atmosphere of the area and the impression arising from the outdoor advertisements using the pictures of street scenes on video monitor. In this experiment, eye movements of each subject observing the scene were analyzed by eye point recorder. (1) In general, vivid red, yellow, green and blue, and white and black were frequently used on the outdoor advertisements in every area. (2) The character of each area was respectively found out by analysis of the following factors: the type of advertisement, the size of each advertisement, and the arrangement of the advertisements. Vivid colors on the outdoor advertisements could be clearly perceived even from a distance. Then, our eyes would be attracted by vivid colors of them. (4) The atmosphere of the area would be affected by favorable or unfavorable impression from the outdoor advertisements. For instance, on the main street, the advertisements would impress us favorably if they are in harmony with each other and create an orderly and elegant streetscape. On the shopping street, various advertisements would impress us favorably if they create a lively and cheerful streetscape.
The main goal of our project is to make VR applications usable for the planning of light and color. To enable reliable simulations, we both need to develop better rendering methods and carefully study the appearance of light and color in real rooms and in virtual environments. Assessments of real rooms are compared to simulations of the same rooms in immersive Virtual Reality (3D-cube). In this paper, we will present the outcome of a pilot study and discuss specific problems associated with the prospect of comparing reality to Virtual Reality. We will account for the experience of the room and go into details on the experience and perception of light. Indeed, the problems fo getting enough light in the 3D-cube and of simulating the light situation of a real room affect color appearance.
Light filled in a room consists of direct and mutual reflected components. Thus the color of light shifts physically to that of an interior of a room when the interior is colored. However, it is not understand how we interpret this color shift caused by the mutual reflection. In this study, we examined how we interpret the color of light filled in a room by using a light source color matching method. The test box had the chromatic interior and those of the matching box achromatic. The results indicated that subjects perceived the color shift produced by the mutual reflection as belonging to the light source.
Color in architecture is not a simple perceptual entity, but is perceived relatively to space and time, material and form, light and surface, as well as movement, action and characteristics of the user. The actual color image is a constant flux of changing and overlapping scenes, which are the result of the compound effects of various factors. According to our experience in simulating light and color at the Department of Spatial Simulation at the Vienna University of Technology we may conclude that this complex interplay can not be studied adequately other than by means of full-scale modeling. 1998 we developed a full-scale model of an interactive color space. 1999 Melanie Yonge set up a similar model in New Zealand, which we used for workshops. 2000 we built 'Luminos 3' - The Colour Light Labyrinth: a mobile and interactive installation offering a unique opportunity to develop and explore, teach and research color design concepts in the context of space, movement and time. 'Luminos 3' is a step further to bridge the gap between theory and practical application, imagination and reality. This presentation reports our experiences with it and discusses its potential for exploring and assessing color and light in 3D.
When Australia was first colonized by immigrants from Britain in May 1829 they brought with them the social and cultural conditioning that was their heritage in the Northern Hemisphere. This included entrenched attitudes about what was deemed to be appropriate behavior, which depended on age, class, wealth, martial status and gender. In post Industrial Revolution England there was an inherent conflict between the capitalist industrialized world of manufacture, and the domestic realm, which was perceived to be a moral and spiritual refuge from work. A solution to this dichotomy was to separate the two, with the industrialized world seen as the male domain and the domestic sphere seen as the female realm. Within the walls of the home, though, spaces were also allocated a gender depending on their function, and this was reinforced through the use of applied color to the domestic interior.
The influential architect Le Corbusier (1887 - 1965) was also involved in the adventure of contemporary painting, and color occupied half of his day, during twenty years, as he revealed in a study entitled 'Architectural Polychromy' written in the early thirties and recently published in 1997. In the present, contemporary architects in Central Europe are dealing with color in quite a different and exceptional way: most of them engage the artist to collaborate with them in their architectural projects. If painting is concerned with the interaction of color in the two-dimensional plane, architecture is deeply dependent on light and space, and deals entirely with the three- dimensional environment and its human perception. In the 1990s, the way architects and artists employed color in architecture was so striking that color offered a key to larger discussions and opened up an interesting aspect of architectural practice. It must be remembered that recent housing projects, such as the housing estate Pilotengasse in Vienna, Gigon & Guyer's Broelberg in Kilchberg (with Harald F. Muller), next to Zurich, and their Sport Center in Davos (with Adrian Schiess), Jean Nouvel's Cultural and Congress Center in Lucerne, or Sauerbruch & Hutton's Photonic Center and their GSW office building in Berlin have all been contributing to free color from its unconscious and dormant role. These works all impart qualities to color in architecture that were hitherto reserved to other materials and fields: they define the aspects of the interaction of visual and physical space, of materialization of volumes, and of the expression of wealth and luxury.
In Urban Spaces and in Architectures information appear days and nights, using as medium the various color appearances and texture aspects support. Meaning, identity, evocation, harmony ... will depend from 'color words' organization.
Characteristics of color constellations observed in the Seattle cityscape were as follows: (1) The higher the chroma of hues within the color constellation the more distinct it became. These colors advanced and often appeared to float in a plane independent of the objects of which they were a part. Chroma was the most important characteristic in these constellations. (2) Hue variations within constellations were two steps on the NCS Index (i.e. Y70R to Y90R), and nuance variations were 10% or less (i.e. S1080 to S2070). (3) Color elements in a constellation were usually seen as fragments of buildings, structures, and objects in which their three-dimensional shapes we not as obvious. (4) Size and shape were similar in most color constellations observed.. (5) Color constellations in chroma below c=50 were observed where distance, light, and/or atmospheric conditions obscured edges and the visual field appeared two- dimensional. This was consistent with Swirnoff's findings in model studies where color was the dominant factor in organization only to the monocular observer. (6) Color elements in a color constellation below c equals 50 occurred where background contrast was minimal. (7) Three or more color elements were necessary for the formation of a constellation.
Colors used for commercial signboards, displayed outdoors as well as indoors through windows, such as a store sign, an advertising sign, a sky sign, a poster, a placard, and a billboard were extensively surveyed in Kyoto City, Japan, in 1998. The survey showed that various kinds of yellow painted signs have increased rapidly and invaded a center area and suburbs of the city. Vivid yellow, what we called it the Y98 virus, is specially considered a color unpleasantly matched to the city image of Kyoto which was the capital of Japan for nearly 1000 years (794 to 1868) and is endowed with cultural and historic heritage. Discussions trying to find out what we could do to prevent the rapid spread of a big commercial display painted with vivid yellows what we called 'the Y98 virus' over the city will be summarized in a main text.
The main objective to be achieved in my research work is to preserve the traditional coloring of the country-houses in the Northern Hungary, at least defined - measured the colors - and in photos. The coloring traditions of the country- houses are more than a hundred years old. These are based on people's impulsive color choice. The golden age of the vernacular ornamentation developed from the middle of the XIX.c. The places of the ornaments obviously first of all are on the streetfronts of the houses. Whitewashing the walls developed in a lot of villages because some settlements ordained it. Some signs shows that blue painting of the walls -- which was made first by blue mineral matters, later industrial paints - preceded or was in the same age as whitewashing. Still, we can say, that the tricom harmony of red, yellow and blue colors and the complimentary harmony of the yellow and blue colors are generally received on the original peasant-houses of the area. The lightness of these colors are average, but the saturation was intensive which was liked in the Middle Ages. You can find such houses nearly in every village. There are everywhere in the territory whitewashed houses with colored pedestal, too.
Author(s): Jin-Sook Lee; Chang-Soon Kim; Oh-Yon Yim; Deok-Hyung Lee
This study is aimed at making index with series of experiments in order to adjust the change occurring by an area effect in architectural color design. The basic experiment was performed to find the change of color regularly in the condition of fixing regular area and viewpoint.
Every form is as sensitive as a puff of smoke, the slightest breath will alter it completely. Kandinsky-- The interaction between form and color regarding this mutability of meaning is a subject that is ever elusive. At the same time, it remains a subject that merits objective and collective study, not so much to generate finite conclusions but to increase our visual awareness and sensitivity of the complex phenomena at work. Much has been accomplished but it still remains an all but unanswered question. Color effects need to be seen to be believed and, as Albers stated in his Interaction of Color, theory should follow practice. This paper presents recent developments in my painting practice by exploring the combined effects of color phenomena through systematic practical experiment with changing color forms. The work is systematic but embraces the intuitive, the sensual and the magical - closing the gap between intuition and formula. The wide range of meanings (associations, evocations, emotions) that Mark Rothko obtained from subtle changes of form and color in the rectangles- within- rectangles format of his mature paintings, is evidence of the scope of this line of research.
Our work deals with the color of the city. We propose the study of the urban built landscape chromaticity, here in Rosario, Argentina. We're trying to find out the reasons that make our city looks in gray. The project we're developing is based in the fact that urban environment has a color, that is to say that, a dominant color that makes the inhabitants feel the urban space that way. We think that it may be introduced into the traditional tools used to study the urban development dimensions like color at the time to interpret the urban environment. The research and survey let us show the great importance that color has as design instrument, even in the urban dn the building scale. It has been proposed a research model in order to consider the particularities of the city. The model is apply to different paradigmatic fragments so as to know the real color incidence in the perception of the city. The work it's been developed through the following topics: (1) Perceptive survey. (2) Downtown building survey. (3) Historic survey. Based in the interdiscipline work we try to contribute to the design and optimization of the tools that let professionals and researchers understand the complex urban environment so as to make supporting cities.
In this report, we produce the perspective views of 3 houses by using CG. These are 20 pictures making changes the color on a wall and roof. We assess these pictures to use the Method Paired Comparison. The colors on a wall and roof were decided to base on the research according to the color choice on a wall and roof in reference 1.
Author(s): Ferdinand Carabott; Garth Lewis; Simon Piehl
Computer programs like Adobe Photoshop can generate a mixture of two 'computer' colors by using the Gradient control. However, the resulting colors diverge from the equivalent paint mixtures in both hue and value. This study examines why programs like Photoshop are unable to simulate paint or pigment mixtures, and offers a solution using Photoshops existing tools. The article discusses how a library of colors, simulating paint mixtures, is created from 13 artists' colors. The mixtures can be imported into Photoshop as a color swatch palette of 1248 colors and as 78 continuous or stepped gradient files, all accessed in a new software package, Chromafile.
A tragic error is being made in the literature concerning matters of color when dealing with optical fusions. They are still considered to be of additive nature, whereas experience shows us somewhat different results. The goal of this presentation is to show that fusions are, in fact, of 'proportional' nature, tending to be additive or subtractive, depending on each individual case. Using the pointillist paintings done in the manner of Seurat, or the spinning discs experiment could highlight this intermediate sector of the proportional. So, let us try to examine more closely what occurs in fact, by reviewing additive, subtractive and proportional syntheses.
The Three Color Zone notation system is originated in the need that the directors of photography have of working with color together with the illumination. The system offers a tool that uses well known units, such as stops, exposure values (EV), or zones, classifying colors (surfaces or filters) according to the zone in which every layer of the photographic emulsion is exposed. The main idea of the system is to integrate all the aspects that the directors of photography work with. We can also extend the system to color temperature and the color rendering of light sources. The aim of the paper is to show, by means of images, how the system works.
It seems necessary to me to combine a certain technical inventivity with plastic creation, a particular poetry arises from this relation. The sources of inspiration for works, especially works in which color plays a pre-eminent role, do not only come from nature. The fantasy of the creators evolves and changes thanks to discoveries and technological inventions. My work as a painter has made me particularly sensitive to the diversity of the plastic writings in general and to the chromatic writings in particular. (1) Environmental creation imposes a renewal of the means of creation. Conducting experimental works, I study the particularities of light, mainly its incidence on materials (transmission, reflection, colors, textures, etc.) and its mobility. These works are a source of inspiration for my architectural works and nurture my lectures at the Ecole Nationale Superieure des Arts Decoratifs (National College of Decorative Arts). Environmental creation also imposes some qualities on the artist since he, whether he serves a social entity or a person, serves the whole collectivity. Environmental creation has to be envisaged as an altruistic approach.
Visual communication is a key aspect of human-computer interaction, which contributes to the satisfaction of user and application needs. For effective design of presentations on computer displays, color should be used in conjunction with the other visual variables. The general needs of graphic user interfaces are discussed, followed by five specific tasks with differing criteria for display color specification - advertising, text, information, visualization and imaging.
Among thousands of color combination, how to arrange and create color harmony? What is the best ratio in arranging color area? This study is based on 'Tone' concept to arrange the experiments whereas it was developed and issued by Nippon Color Design Research Institute. This study aims to explore how area ratio relate to color harmony. As well the experimental results were used to verify Munsell's Law <<A1(V1C1)equalsA2 (V2C2)>> and Moon & Spencer' Model <<A1[C12 + 64(V1-VB)2]1/2 equals A2[C22+64(V2 - VB)2]1/2>>.
Experience with the Master Palette system of 6000 colors lead to a specification for a new color range where the primary design feature is the control of the paint tint formula. This design approach met a market-derived requirement for sample pots and fractional-strength colors. The layout process employed was able to display the color capability of the paint system and generate an array of colors with controlled spacing similar to Master Palette. Updated pigment selections and the introduction of additional colored bases completed the system specification of improved opacity and every color being exterior durable.
A method to specify and quantify undertone is proposed based on CIELAB color space. This method enables us to deal with colors according to their undertones (their ratio and Lab coordinates). The method also enables us to discuss undertone from the viewpoint of color appearance, being isolated from personal color analysis.
Graphic design is visual communication through the selection, arrangement, and presentation of words and images, most often for the printed page which offer the designer almost limitless options for color use. The objective of this project is to identify patterns of color use. Ethnographic content analysis was used to document color use in annual reports represented in two publications, Print and Communication Arts, 1993-2000. The analysis focuses on the selection, combination, and contrast of hues; and their use with achromatic values. An analysis of the entire sample indicates that one-third of the annual reports used a palette that include black, white, and a hue from quadrant one (red to yellow). Nearly one-fifth of the designs used black, white, and colors from quadrants one and three (cyan to blue). The large samples for Technology, Health Sciences, Financial, and Civic organizations follow the first pattern. Food Service, Business products and services, and Transportation industries favor the second pattern.
During the color perception process, an associated feeling or emotion is induced in our brains, and this kind of emotion is termed as 'color emotion.' The researchers in the field of color emotions have put many efforts in quantifying color emotions with the standard color specifications and evaluating the influence of hue, lightness and chroma to the color emotions of human beings. In this study, a color planner was derived according to these findings so that the correlation of color emotions and standard color specifications was clearly indicated. Since people of different nationalities usually have different color emotions as different cultural and traditional backgrounds, the subjects in this study were all native Hong Kong Chinese and the color emotion words were all written in Chinese language in the visual assessments. Through the color planner, the designers from different areas, no matter fashion, graphic, interior or web site etc., can select suitable colors for inducing target color emotions to the customers or product-users since different colors convey different meanings to them. In addition, the designers can enhance the functionality and increase the attractiveness of their designed products by selecting suitable colors.
<> is the title of an environmental creation which uses a particular lighting device. The site is a baroque chapel which has now become the concert hall of the Music School of Apt, a town in France. One of the properties of the works realized with this device is to be set in front of openings such as stained-glass windows. They take part in the expression of an architecture. In some versions, the lighting is composed of one of several sources of artificial light.
Author(s): Darko Golob; Mojca Strafela; Vera Golob
A novel approach to color design for a fashionable collection of dyed and printed fabric is the incorporating of color management and colorimetry into production process. Color design for the collection is performed on advanced computer-aided color management equipment. This process includes pattern design and scanning, the preparation of color combinations on monitors and their printing out. Individual patterns are prepared in different color combinations. Colorimetry and computer match prediction is used to evaluate the color combinations of fabric collections and to produce recipes for the dyeing and printing processes.
Author(s): Berenice S. Goncalves; Alice C. Pereira; Patricia Neves
This work analyses the use of color in indoor environments, as well as the importance of computer simulation aimed at the study of chromatic harmonization principles. For this purpose, light and tone composition qualities and the characteristics that allow chromatic 'space' construction and perception are explored. This work highlights the very important simulation tool that Computer graphics has became when applied to indoor environment simulation, since the color relations can be better evaluated through the use of virtual manipulation of environmental characteristics and design aims. Finally, some examples are presented which originated from indoor chromatic harmonization-based computer simulation.
Blends and combinations that occur in the world of color are of a great variety. The combinations vary from barely perceptible changes to the most intense contrasts. The vast world of color is explored in search of criteria for its organization, its diversity and complexity being evidenced, identifying three strategic fields for performing work: the surroundings, the object and the perceiver. These fields are recognizable rather than separable as the integration is confirmed in this study. Before this complexity, we decided to begin in a way that contrasts with the nearly most elemental criterion for organizing colors, the criterion of gradation, from complex to simple. The gradual order is a sequential order and of transition between two given color values. In principle, it is an order of linear conceptualization. Let us broaden the approach and consider the line, firstly its single-direction aspect and then in space which is also chromatic, and apply the same criterion of gradation between the structural elements, line and space. We can perceive that the line tends to abandon its limitations, to combine and interact with the surrounding space and shows us with this its freedom, form the simple to the complex.
Color is the most powerful building material of visual imagery on the World Wide Web. It must function successfully as it has done historically in traditional two-dimensional media, as well as address new challenges presented by this electronic medium. The psychological, physiological, technical and aesthetic effects of color have been redefined by the unique requirements of the electronic transmission of text and images on the Web. Color simultaneously addresses each of these dimensions in this electronic medium.
Author(s): Miguel Pena Mendez; Jesus Diaz Bucero; Fernanda Garcia Gil; Joaquin Casado de Amezua; Juan G. Lerma Pelaez; Justo Romero Torres; Santiago Cano Turrion; Rosa Cubillo Robles
The experimental workshop that is presented combines 3 fields. (1) Visual artists (Maribel Domenech and Margo Sawyer); (2) Students, mostly postgraduate level; (3) Teachers/Researchers from the Research Group. It is carried out in the School of Fine Arts, University of Granada, Spain, in May of 2000.
In the recent years there has been an enormous transformation of the western man-made environment in favor of bigger complexity of form, color and mobility. The reasons for this are both sociofinancial (increase of cluster and diversity of population) and cultural (universality, new scientific achievements). It is argued in this paper that color can play a major role in the maintenance of a degree of environmental stimulation favoring cognitive function, well-being and aesthetic reward. This is possible through the replacement of the 'natural selector'-based evolutionary processes by design- based ones, natural selection being impaired by the impossibility of isolation.
The objective of this presentation is to emphasize the importance of lighting in architectural design, and how it can be increased with the use of color. It can be shown, through examples that innovative and creative lighting with color can manipulate one's perceptions and experience of the spaces around them.
A concrete case of the effects of the use as adaptation field of a white-black Ronchi's grating (square grating) on te view of a chromatic periodic test (red or green) is studied here. The influence of the grating orientation on the value of this effect and the minimum frequency under which this effect disappears are determined.
Color is an effective attribute as an aid to a visual task. Appearance of colors, however, remarkably changes with viewing conditions. In particular, lighting environment has strong effects on the appearance of surface colors. To use colors effectively, we must know how colors are identified under various lighting conditions. In our previous studies, we obtained the data on identification of colors under illuminances from photopic to mesopic levels. In this study we examined performance of a color related searching task under photopic and mesopic illuminance levels, and evaluated it based on the color identification data. Subjects searched the target three-digits printed on a card from among 45 cards. At the same time, a color chip was pasted on each plate as a clue. Before each trial the subjects were informed of the number and color name for the target on that trial. If the subjects could identify colors properly,.the searching performance must be improved. As might be expected, the performance of the task declined with decreasing illuminances and size of the color chip. It was found that the searching performance correlated with probability of being identified as the target color.
In order to compare color appearance as seen by elderly and young people, we conducted an experiment where the subjects responded to the color appearance of 75 color chips using a categorical color naming method and an elemental color scaling method. The results show that categorical color naming between elderly and young subjects is almost identical for most color chips, but there were significant differences in the elemental color scaling between the two age groups depending on unique-hue components. The differences in yellow and blue components between elderly and young subjects suggest that the neural mechanism of color vision in elderly people may over perform on constancy of color appearance so as to compensate for the age-related change of the human crystalline lens. In addition, the chromatic components in elderly subjects indicate higher values than those in young subjects for low saturation color chips, whereas the chromatic components in elderly subjects indicate lower values than those in young subjects when viewing high saturation color chips. These results show that the age-related changes of unique hue components strongly depend on saturation of colors, and suggest that the practical range of color appearance in elderly people is small in comparison with young people.
The use of colorimetry within industry has grown extensively in the last few decades. Central to many of today's instruments is the work of the CIE system, established in 1931. Many have questioned the validity of the assumptions made by Wright and Guild, some suggesting that the 1931 color matching functions are not the best representation of the human visual system's cone responses. A computational analysis was performed to evaluate the CIE 1931 color matching functions against other responsivity functions using metameric data. An optimization was then performed to derive a new set of color matching functions using spectral data of visually matched metameric pairs.
The purpose of the present research is to show that color contrast can be also achieved by manipulation of perceived size and to generalize the idea that perceived size is more fundamental to color contrast and assimilation than retinal size of images. In the experiment we assessed color appearance of grating for three color combinations with four stripe widths from 4.6 to 18.6 min. at three vergence angles. Assimilative/contrastive color shift occurred when the vergence was larger/smaller and stripe appeared narrower/wider. Since both of stripe width of retinal image and subject's vergence affect perception of stripe width, we analyzed the size and direction of color shift in terms of perceived width. It was shown all color shifts were attributed to change in perceived width, which suggests perceived dimension is more fundamental then retinal dimension in color perception.
Author(s): Francoise Vienot; Fatima Benhalima; Hans Brettel; Bernard Bourdoncle; Alain Colonna de Lega
This study aims at establishing the relationship between the spectral transmission characteristics of tinted ophthalmic lenses and the visual percept of the observer looking through. We hypothesize that the rating of tinted lenses originates from what the observer sees rather than what the glass looks like. We develop a model for color acceptance by calculating the color distortions for a collection of colored surfaces that are representative of the real environment using the spectral reflectance of the surfaces and the spectral transmittance of the lens. Then we apply the model to a collection of real tinted ophthalmic lenses and derive statistical indices that describes the global color distortion induced by each lens. Preliminary results show a significant agreement between the subjective rating and the objective color distortion index. We conclude that our model allows to predict the acceptance/rejection judgement of observers for a tinted ophthalmic lens of known spectral transmittance.
Author(s): Yasuki Yamauchi; David R. Williams; David H. Brainard; Austin Roorda; Joseph Carroll; Maureen Neitz; Jay Neitz; Jack Calderone; Gerald H. Jacobs
Unique yellow is considered to represent the equilibrium point of the red-green opponent chromatic mechanism. There are several hypotheses that attempt to explain how this equilibrium point is established. The determinant for unique yellow, however, has not yet been clarified. Here we explored whether the L/M cone ratio or visual information determines unique yellow. If the former is the case, we expect that subjects with large differences in their L/M cone ratio would set different spectral lights to appear as unique yellow. The results of such an experiment, however, did not show a substantial difference in the value of unique yellow for two subjects with very different cone ratios. On the other hand, if the latter is the case, unique yellow should change when altering the chromaticity of the surrounding visual environment. To test this hypothesis, we conducted long-term adaptation experiments, in which subjects spent 8 to 12 hours in a chromatically altered environment. A significant shift of unique yellow was observed after spending time in such an environment for several days. These results indicate that the red-green opponent channel includes a plastic normalization mechanism that adjusts its balance point based on visual experience.
Author(s): Miyoshi Ayama; Marjukka Eloholma; Mikko Hyvaerinen; Tetsuya Eda; Daisuke Kon; Kenji Mukai; Sueko Kanaya; Liisa Halonen
In this study, we conducted the experiment to compare the whiteness perception of Finnish and Japanese observers. The rank order of perceived whiteness among seven nearly white Munsell chips (Value is 9.25 or 9.5, Chroma is 0, 0.5 or 1.0) under the fluorescent lamps of correlated color temperatures of 3000K, 5000K, and 6700K was determined. Observing condition employed in the two laboratories was exactly the same as well as the experimental procedure. In 3000K condition, the results of Japanese and Finnish observers agreed with each other quite well, while as the correlated color temperature becomes higher, the results from the two laboratories showed different tendencies. Negative correlation was found between the whiteness rank order and the metric chroma for all of the results.
The extra-brightness which characterizes fluorescent colors was adjusted to determine the luminance threshold dividing surface and fluorent colors for 7 zero-blackness reddish nuances (NCS notation) following three different psychophysical methods. Results are consistent with Evans' findings that threshold is always lower than surface-white luminance and decreases with chromaticness. When the same colors are observed over an achromatic Mondrian in a black viewing box fluorescence impression not only increases with the sample chromaticness, but also with the general illumination and the anchoring level of the Mondrian.
The recently published Matlab implementation of the retinex algorithm has free parameters for the user to specify. The parameters include the number of iterations to perform at each spatial scale, the viewing angle, image resolution, and the lookup table function (post-lut) to be applied upon completion of the main retinex computation. These parameters were specifically left unspecified in since the previous descriptions of retinex upon which the new Matlab implementations were based do not define them. In this paper we determine values for these parameters based on a best fit to the experimental data provided by McCann et. al.
A uniform color space based on color vision mechanisms was proposed. The mechanisms considered to construct the uniform color space were, proportion of three types of cones, compressive response nonlinearity at receptor and post- receptor stages, constant noise or dark response added to the receptor response, and fractional expressions of opponent and S channel in the postreceptor stage. The present uniform color space explains, three dimensional color discrimination data, supra-threshold color differences such as Munsell color chips, and luminance dependence of the color differences.
We suggest that color constancy and perceptual transparency might be explained by the same underlying mechanism. For color constancy, Foster and Nascimento (1994) found that cone-excitation ratios between surfaces seen under one illuminant and cone-excitation ratios between the same surfaces seen under a different illuminant were almost constant. In the case of perceptual transparency we also found that cone-excitation ratios between surfaces illuminated directly and cone-excitation ratios between the same surfaces seen through a transparent filter were almost invariant (Westland and Ripamonti, 2000). We compare the ability of the cone-excitation-ratio invariance model to predict perceptual transparency with an alternative model based on convergence in color space (D'Zmura et al., 1997). Psychophysical data are reported from experiments where by subjects were asked to select which of two stimuli represented a Mondrian image partially covered by a homogeneous transparent filter. One of the stimuli was generated from the convergence model and the other was a modified version of the first stimulus such that the cone- excitation ratios were perfectly invariant. Subjects consistently selected the invariant stimulus confirming our hypothesis that perception of transparency is predicted by the degree of deviation frm an invariant ratio for the cone excitations.
This study aimed to evaluate psychological impression of visual comfort when we see an image of ordinary colored scene presented in a color display. Effects of opponent colors, i.e. red, green, yellow and blue component, on the subjective judgement on visual comfort to the image were investigated. Three kinds of psychological experiment were designed to see the effects and the results indicated that the red/green opponent color component was more affecting than the yellow-blue one, and red color in particular was the most affecting factor on visual comfort.
This paper reviews and critiques earlier version of the ATD model, and it describes a revised model, which differs mainly in its gain control function. The model is applied to recently published lightness, hue and colorfulness data.
We found an interesting phenomenon concerning the motion perception and the mode of color appearance. We suppose you are holding a stiff sheet of picture and move it laterally to and fro in front of the eye. Though the picture and all items in it move physically altogether with your hand, your perception is not always so. But when the picture that is a figure appears light-source color mode and a background of object color, a figure appears to slip on a background. We call this a 'floating phenomenon.' We predicted the occurrence of floating phenomenon depends on whether the color is perceived to belong to an object or not. To examine the relation between the floating phenomenon and the mode of color appearance, we measured the luminance threshold of floating phenomenon and the transition luminance between two color modes by constant stimulus method to use a mondrian. Our results show the floating never occurred when the target appeared as object color mode. The floating phenomenon may be caused by the separation of the light-source color from an object or week-belonging.
The purpose of this study is to investigate the characteristics of color in more detail, especially on the perception of depth, to verify the order of the color coordination that amplify the perceptual depth on the computer mediated drawing. It can draw interesting achievements to valid expression in the new method of three- dimensional presentation. On CRT display, in the case of the stimuli that different wavelength set with luminance difference and the other case of the stimuli that different wavelength set with same luminance on the bright peripheral visual field (white) were discussed in the previous report. In this paper, I reported the results of some observation on the dark peripheral visual field, gray (some luminous as the stimulus) and black, in the same manner to discuss the luminous effect of the peripheral visual field on the basis of comparison with the results of the blight peripheral visual field. In the results, the influence of the luminance of the peripheral visual field to the perception of the superiority or inferiority and occurrence of the qualitative change are recognized. Almost of those phenomenon seems quite probable that occurred results in the contrust of the luminance factor including the characteristics of each dominant wavelength. 13
Full-color imaging requires four channels as, in contrast to a colorimeter, can add no primary to matched scene colors themselves. An ideal imaging channel should have the same spectral sensitivity of scene recording as a retinal receptor and evoke the same primary color sensation. The alternating matching functions of a triad of real primaries are inconsistent with the three cones but explicable of two pairs of independent opponent receptors with their alternating blue-yellow and green-red chromatic axes in the color space. Much other controversy of trichromatic approach can also be explained with the recently proposed intra- receptor processes in the photopic rod and cone, respectively. Each of their four primary sensations, unmixed around 465, 495, 575, and 650 nm, is evoked within a different spectral region. The current trichromatic photographic systems have been found separately to approximate the blue and red receptors, as well as their spectral opponency against the respective yellow and blue- green receptors simulated with a single middle-wave imaging channel. The channel sensitivities are delimited by the neutral points of rod and cone and cannot simulate the necessary overlap of non-opponent channels for properly to render some mixed colors. The yellow and cyan positive dyes closely control the brightness of blue and red sensations, respectively. Those red and blue respectively to control the yellow and blue-green sensations on brightness scales are replaced by magenta dye, controlling them together. Accurate rendering of natural saturation metameric colors, problematic blue-green, purple-red, and low-illumination colors requires to replace the hybrid 'green' channel with the blue-green and yellow channels.
Since 1991 the HVC Color Vision Skill Test has been available worldwide. Initial technical information was published in1993. Further data allow additional conclusions with regard to sex and experience of observers. However, the conclusions reported in 1993 have been revalidated and remain unchanged. No essential difference in scores show up in the comparisons of male and female observers. Workplace experience comparisons for those who deal surface colors and those working with CRTs favor surface color in the limited data reported.
253 visual observers, at the average level of between 'unselected' (inexperienced) and 'in-plant applicants' have been tested under controlled industrial conditions using the Ishihara or T.M.C. (Murakami) pseudoisochromatic plates, the Farnworth-Munsell 100 Hue Test (FM), the HVC Color Vision Skill Test (HVC) and the Japanese Color Aptitude Test (JCAT). There is only loose correlation between the FM and the HVC tests. The FM scores do not improve significantly by retesting, while the HVC scores can be improved through training, e.g. by using the JCAT. We found practically no correlation between the performance in visual pass/fail decisions and the FM or the HVC scores. Three different editions (3 copies from 1991, 3 from 1997 and two from 1998) of the HVC test were measured and analyzed. They showed good, in the latest edition very good, intra-edition repeatability and good inter-edition reproducibility.
When we are viewing colored picture, what is the difference in our brain between a random Color dot picture and a digit figure pattern picture seen through its colored dots? We created 3 patterns that are a functional magnetic resonance imaging version of the Ishihara plate patterns to test multiple color-sensitive areas in human ventral occipitotemporal cortex. The results showed that area V4 is activated by the stimulus of reading shapes from its color dots in the Ishihara pseudoisochromatic plates but not by the stimulus of seeing a random color dot picture. We suggest that area V4 is activated not by color processing but by segregation.
Brightness differences between an overlapping area of two figures and a surrounding area as a background effected to bring apparent transparency at the area. Regarding this phenomenon of a sense of transparency, there were two kinds of a sense being related to either depth or interposition. In this paper we analyzed conditions of a figure-background brightness relation in terms of contrast and assimilation evoked these two senses of transparency at the area. A sense of transparency of the area located apparently in a space of three dimensions produced a sense of depth by a brightness contrast effect between the crossing area of two figures and its surrounding background. On the other hand a sense of transparency of the crossing area of two figures as seen in a space of two dimensions produced a sense of interposition when assimilation occurred between the area and its surrounding background.
Author(s): Maria L. F. de Mattiello; Maria M. Chague; Susana Buglione
We analyzed how much motion coherence was needed to detect a target group of three moving dots in a dynamic visual noise background and how the addition of color helps to achieve this coherence. In order to do this, 171 different situations were analyzed: the amount of noise dots, three different organizations of the samples, and different achromatic and chromatic situations both in the backgrounds and in the samples. The results indicate that: collinear targets are easily recognizable; in an achromatic situation the increase of noise dot produces a sharp decrease in recognition; color of the dots, particularly if the color is in opponence to the background color, re-establishes this loss. The results also indicate that movement and form regularity do not appear to be additive but are interactive.
After a brief report on the gap existing between the visual functionality assessed in the constrained laboratory conditions and its applications in the complex, multidimensional, real world, two examples concerning color appearance are described in the former experiment we wonder why a colotimetrically uniform, 10° diam. test field has a uniform color appearance, in spite of the eccentricity dependence of the color naming for a 1° diam exploring spot. It is as if the underlying gradient of responsiveness of the underlying array of photoreceptors were discounted. But this does not tell us what is the actual color appearance. Less distal mechanisms resulting in assimilation or filling-in are to be called into play. In the second experiment we consider as test objects the modern, expensive, flashy cars. Although coated uniformly, under natural outdoor lighting they appear as a complex set of segmented 'regions' differing in lightness and even in hue. However, simultaneously and effortlessly, we perceive a coexisting idealized uniform surface color, probably reconstructed as if the perturbation due to natural lighting, responsible for the segregation into regions, and the gloss responsible for intra-region textures were discounted.
However many research suggest that chromatic information is not used to perceived motion, some reports suggest the possibility of effect of color on motion perception. The correct ratio of motion direction judgement was measured in this experiment in which isoluminant stimuli were presented. The results suggest that color may have some effects to motion direction judgement.
Understanding of illumination performs an important role in perceiving the color and brightness of object's surface. Especially, we can evaluate observer's perception about intensity of illumination by the concept of the brightness size of recognized visual space of illumination, RVSI. Our previous work showed that the RVSI size is determined by the luminance of a highest-lightness object and it's normally proportional to the illuminance. In the present experiment, we measured the border luminance between object color and unnatural object color in two rooms differently furnished, to examine the effect of color scheme of interior on the brightness size. In spite of the same illuminance, the border luminance was a half of that in normal environment when the room was furnished with only objects whose Munsell Value were 5 or less. The measurement of the border luminance was not affected by local illuminance or immediate background. It indicates the RVSI is unique for a room: only one measurement is enough. It can be a great advantage when the measurement is applied for real and complex environments. The RVSI size may be a useful and easy measure for evaluation of the adaptation level of the visual system in practical and complex environments.
Author(s): Kristian Samu; Klara Wenzel; Karoly Ladunga
The experience of a colored picture is formed of the multitude of spots of different colors and shapes projected on the retina of the eye. The more spots we can distinguish the more details we can see and the more information we can get. It can be observed that people of anomalous color vision are at a disadvantage not only from the point of view of the correct recognition of colors but also from that of seeing less detailed than do that of normal trichromats. It is rather difficult to measure the detail of colored pictures formed by seeing. It is practical to carry out the measuring with simplified geometry and in limited colors. The most simple test picture is the grating and it is best to limit the colors to two and to their additive mixtures respectively. The color contrast sensitivity function (CCFS) can be well used to prove that people of anomalous color vision can distinguish less details than those of normal trichromats. Besides this the effect improving color vision (e.g. by color vision correction filters) can also be proved. Several examinations can be made by gratings created with two colors and by changing their various parameters . We have got appreciable data by changing space frequency and contrast, and redefining colored gratings to the CCSF already known in the examination of sight testing. Thereby we succeeded in demonstrating the difference between normal and anomalous trichromats.
We used the samples prepared by letting the background stimulus color change so that the size of contrast will differ from the test stimulus color in various ways, studied the relation between contrast and advancing color in the three directions of value, chroma, and hue, also let the illuminance level change, and examined the influence of Purkinje shift. As a result, we found in the value contrast and chroma contrast that in any hue, as the contrast with the background becomes higher, the stimulus looks closer, and we could not observe any influence of Purkinje shift. However, in an experiment in which only the hue is different at the same values of the value and chroma between the test stimuli, we could observe the influence of Purkinje shift in that, when only the background stimuli is N1, a blue color looked most advancing in the mesopic vision, whereas a red color looked most advancing and the blue color did not look advancing in the photopic vision.
We study here the feasibility of a spectral daylight recovering algorithm using a linear model that takes advantage of the strong correlation among daylight curves. To test the algorithm we use the daylight eigenvectors obtained by a principal-value decomposition over 2600 daylight spectra recorded over a period of two years. A binary search, performed here, found the optimal spectral positions of a set of few narrow-band filters. We analyze, over the set of 2600 daylight curves, the algorithm accuracy when using three to six narrow filters, obtaining that such an daylight algorithm is not sufficiently accurate in comparison with similar linear models that recover objects spectral reflectances proposed in artificial-vision.
Color and visual appearance of materials are presented within the general framework of their optical properties, described with the unique notion of complex index of refraction. We limit our investigation to materials described as homogeneous and forming a continuum at a macroscopic scale of observation, though there exist some methods for extracting optical data from spectral curves. Previous works due to John W. T. Walsh in 1926 are recalled and generalized with the help of the 3D computer simulation of the Surface of Whole Reflectivities.
Some shells from both salt water and fresh water show the phenomenon of iridescence color. Pearls and mother-of-pearls also display this phenomenon. In the past, the cause of the iridescence color was attributed to interference. A scanning electron microscope (SEM) was used to study the surface structure of the shell of the mollusk Pinctada Margaritifera. There is a groove structure of reflection grating on the surface area in where the iridescence color appears. An optic experiment with a laser obtained a diffraction pattern produced by the reflection grating structure of the shell. The study led to a conclusion that the iridescence color of the shell is caused by diffraction. A SEM image of the shells of an abalone Haliotis Rufescens (red abalone) showed a statistically regularly arranged tile structure that serves as a two-dimensional grating. This grating structure causes the iridescence color of the shell of red abalone. The dominant color of the iridescence of shells is caused by the uneven grating efficiency in the visible wavelength range when a shell functions as a reflection grating. The wavelength of the dominant color should be at or near the wavelength of the maximum efficiency of the grating.
Author(s): Lilyana S. Yourukova; Kroum M. Kolentsov; Todor Kehlibarov
An original hybrid technology is used for the preparation of electroluminescent display structures of various color emission. Some new aspects in the brightness and color investigations of these structures will be reported. Brightness B and color parameters in the CIELUV of structures under various excitation conditions are discussed. The possibility to use these display structures in various informational systems in the up-to-date society and their advantages are indicated.
In the late 19th century, the Gestalt Psychology rebelled against the popular new science of Psychophysics. The Gestalt revolution used many fascinating visual examples to illustrate that the whole is greater than the sum of all the parts. Color constancy was an important example. The physical interpretation of sensations and their quantification by JNDs and Weber fractions were met with innumerable examples in which two 'identical' physical stimuli did not look the same. The fact that large changes in the color of the illumination failed to change color appearance in real scenes demanded something more than quantifying the psychophysical response of a single pixel. The debates continues today with proponents of both physical, pixel-based colorimetry and perceptual, image- based cognitive interpretations. Modern instrumentation has made colorimetric pixel measurement universal. As well, new examples of unconscious inference continue to be reported in the literature. Image processing provides a new way of analyzing familiar Gestalt displays. Since the pioneering experiments by Fergus Campbell and Land, we know that human vision has independent spatial channels and independent color channels. Color matching data from color constancy experiments agrees with spatial comparison analysis. In this analysis, simple spatial processes can explain the different appearances of 'identical' stimuli by analyzing the multiresolution spatial properties of their surrounds. Benary's Cross, White's Effect, the Checkerboard Illusion and the Dungeon Illusion can all be understood by the analysis of their low-spatial-frequency components. Just as with color constancy, these Gestalt images are most simply described by the analysis of spatial components. Simple spatial mechanisms account for the appearance of 'identical' stimuli in complex scenes. It does not require complex, cognitive processes to calculate appearances in familiar Gestalt experiments.
When we give name to color, we usually describe our perception of light, as compared with our own experience and knowledge. Very often perception of color is a complex problem that needs to be described by mathematical, physiological, and physical theories. There is a clear description for the physical task of describing quantities for mixing color pigments. In this article, the author discussed original graphical decision for color equations: the color surface for natural mixtures. Light mixing theories describe the nature of color, originally in mathematical language of the physical principles for color mixing different substances. Color-mixing system were originally developed based on the three-component chromatic model, which tells us how color works in nature and how color mixing works with pigments. Color theory was developed to show how color pigment structures could be measured. In this article, an algebraic system is shown consisting of mathematical equations, given the surface of color mixing, gives measurement principles of color characteristics by the two quantities. This mathematical system has shown by graphical decision color mixing the nature of the physical 3-component vision. The original model of mixing equally well provides the numerical identification for color mixtures of two or three components pigments. Clear descriptions of colors on the color surface show the different characteristics of color, and the value that these colors have in light mixing as estimated by the vision perception system. Color surface is very important as a practical conception for understanding the quantitative description of color measurement technology. The color surface as a graphical model is mathematically necessary to describe the mixing color components of pigments, lights, and substrates. Each single color is positioned as a sum of several primary colors and can be applied in the separate physical task of measuring color, to reproduce color by technology. Color as the physical characteristic of a substance has the practical meaning in every day practice to guide through many types of color variations. Clear understanding and interpretation of color values is consist with the mathematical equations for color components, reproducing the white light absorption, reflection by the substances with regular color chemical structure, and describing substances such as solid, gases, liquids, organic, inorganic. In this article, an evaluation of the spread of chemical pigment components in growth process plants is demonstrated. We also studied seasonal fluctuations of organic pigment components with the example of ripeness for maturing fruits. We have discussed color structure spreading for toxic smoke, with visualization of the concentration of toxic substances in an open-air environment. Application of color surface for color digital measurement is practical in cases for color pigments spreading of chemical structures. This article has shown research result in organic fruit specimens, Sorby 'rowanberry,' a well-known medical plant, and specimens of toxic smoke. Color studies are necessary to get the quantitative description pigment structure in original specimens, technical identification color pigments. Color surface has important meaning for the physical perception of world.
We construct a class of infinite planer simple graphs that are continua and have the fractal property where the faces of their regions are either triangles or nonconvex pentagons. We choose to embed them in Euclidean two space or plane with the natural product topology which makes them normal topologically. Any one of these continua is sufficient to exhibit all the color or hue names and arities of formation that are created by mixing two primary color units of any chroma or value at proportions that are equal. We call our continuum the Even Proportional Color Triangle (EPCT) and prove that it is a continuum. Functions are made between an infinite discrete proper subset of one EPCT and a set of polynomials to represent the hue names and the set of natural numbers to represent primary, binary, ... color units or color arity given by mixing color units. We formulate MacAdam Hue Limit Theorem (MHLT) which represents the first formal mathematical statement of an observed property of color mixture, which is a panoptic theoretic interpretation of a theorem from real analysis. EPCT can be used to define other continua and it has important properties of dimension theory and yields lemmas and corollaries.
Author(s): Miho Saito; Junko Matsumoto; Akira Date; Junfang Li
Beauty is a world common aspiration, but perceptions of what make a woman beautiful vary across culture and countries. A series of Saito's studies indicated that unlike much of the Western world, in Asia, one common desire is fairer skin tone that epitomizes feminine beauty. Using 105 Japanese women and 105 Chinese women as subjects, a comparative study concerning aspiration of Asian Women toward skin fairness was conducted. In this study, four real skin photo images that have skin tone variations (fair/dark) and skin texture variations (rough/smooth) were used. The fifty-two words describe personality were shown to the subject. The subjects were required to match a suitable skin photo image to the descriptive words. The overall result between China and Japan were very consistent. Both in China and Japan, fairer skin tone with smoother skin texture was accepted very positively. Fairer skin tone with rougher texture tends to provide passive and conservative impression while smoother skin texture with darker skin tone tends to provide friendly and delight impression. The results suggested that in addition to skin tone, the skin texture plays an important role for the personal impressions and it works as a trigger to enhance 'ideal skin fairness' for Asian women.
In order to investigate preference responses for foreground- background color relationships, 85 university undergraduates in Ankara, Turkey, viewed 6 background colors (red, yellow, green, cyan, blue, and magenta) on which color squares of differing hues, saturations, and brightnesses were presented. All the background colors had maximum brightness (100%) and maximum saturation (100%). Subjects were asked to show the color square they preferred on the presented background color viewed through a computer monitor. The experimental setup consisted of a computer monitor located in a windowless room, illuminated with cove lighting. The findings of the experiment show that the brightness 100%- saturation 100% range is significantly preferred the most (p-value < 0.03). Thus, color squares that are most saturated and brightest are preferred on backgrounds of most saturated and brightest colors. Regardless of the background colors viewed, the subjects preferred blue the most (p-value < 0.01). Findings of the study are also discussed with pertinent research on the field. Through this analysis, an understanding of foreground-background color relationships in terms of preference is sought.
This paper proposes the necessity of manipulating colors of movie contents to fit diverse audiences around the world. Since films are highly color-dependent messages, it is critical to understand how people in different cultures respond differently to color. In recent years, the international market for filmed entertainment has grown more than the U.S. market. However, a lack of research on audience preferences shows no constant guide for the motion picture industry. The film production stage is often disregarded to deliver the appropriate visual color contents for local audience when U.S. films are distributed to foreign markets. Therefore, it is assumed that it would cause distractions for local audiences and it could result in poor ticket sales. When the U.S. produced films are distributed in Asia, colors of original films are always shown without manipulation. It is common that when a U.S. manufactured car is imported to Japan, a driver seat is installed on the right side and also other parts are modified for local customers. Film development is also significantly dependent on audience behavior, so film content also needs to be localized for the different culture. This paper will only address a hypothesis of the implementation of color marketing methodology present in motion pictures.
Chinese believe that Feng-shui, Ch'i, Tao, Yin and Yang are major components rooted in Chinese culture. Many people know life has to balance and harmonize with nature and the universe through the Five-essence. Ancient wisdom is successfully interwoven with mankind and the natural world. Elements such as orientation, season, color, sound, facial organs, viscera, stars, and numbers can be associated with life through the Five-essence Theory. Since color is one of the major components of the Five-essence Theory, everything in our life can be associated with colors through a conjoined covering process. Color selection process is part of the interaction between human beings and the universe. Depending on the achievement one is pursuing, the Five- essence Theory model can be treated as an interface between destiny and human beings. This study reports how life is associated with Chinese Five-essence based paradigms. Models were used to explain how Chinese utilize Five-essence Theory to select colors in their daily lives.
When people enter a gym, they feel more like exercising in some cases than other cases. The interior color of the space may be a contributing factor. This paper discusses how the interior color of a gym affects female subjects in their twenties and forties to fifties both physiologically and psychologically.
Author(s): Tetsuya Sato; Kanji Kajiwara; John H. Xin; Aran Hansuebsai; Jim Nobbs
Human emotions induced by colors are various but the emotions are expressed through words and languages. In order to analyze the emotions expressed through words and languages, visual assessment tests against color emotions expressed by twelve kinds of word pairs were carried out in Japan, Thailand, Hong Kong and UK. The numerical expression of each color emotion is being tried as a formula with an ellipsoid-shape resembling that of a color difference formula. In this paper, the numerical expression of 'Soft- Hard' color emotion was mainly discussed. The application of color emotions via the empirical color emotions formulae derived from kansei database (database of sensory assessments) was also briefly reported.
The research for basketball has been focused upon the color effect on the team shirts by means of sports and colors. University basketball club members and university students (who did not belong to the university basketball club members) participated in this study. Colors of team shirts were analyzed by A.H. Munsell's method (Hue, Value, Chroma). To each of four games were given four different color conditions: The first is on condition that players of both teams wore different five-colored team shirts (white, red, blue, green, orange).The second is on condition that all players of both teams wore white team shirts. The third is on condition that all players of the one team wore red team shirts and the others wore orange. The fourth is on condition that all players of the one team wore blue team shirts and the others wore green. The questionnaire, the number of shots, and passes were analyzed of statistics (x2 :1 X m contingency table) on the above mentioned conditions. The results were as follows: (1) The number of successful shots that university basketball club members made were higher than university students. (2) The number of unsuccessful passes that university students made were higher than university basketball club members. (3) Analyzed by statistics (x2:1 X contingency table), the apparent distinction of the color effect was not found. These results could be due to players requirements of momentary judgement such as their recognition of the other players face or voice. This seems to depend upon different factors of the subject himself on a physical strength level as well as on a technical level.
In color preference and color-meaning research, color chips are widely used as stimuli. Are meanings of isolated color chips generalizeable to contextualized colors? According to Taft (1996), few significant differences exist between chip and object ratings for the same color. A similar survey was performed on 192 college students. This article reports the results of the study comparing semantic rating of color applied to a variety of familiar objects. The objects were a cup, T-shirt, sofa, car, notebook, and MP3 player, all images that represent daily life familiar objects. Subjects rated a set of 16 color chips, against 6 bipolar, 7-step semantic differential scales. The scales consisted of beautiful-ugly, soft-hard, warm-cool, elegant-vulgar, loud- discreet, and masculine-feminine. Analyses performed on the data indicated that unlike Taft's findings on 1996, significant differences existed between chip and object rating for the same color in every scale. The results of the study have implications for the use of color chips in color planning which suggest they are not compatible with the generality of results of the earlier color meaning research. Generally, a color judged to be beautiful, elegant and warm when presented as a chip does not equal beautiful, elegant, and warm when applied to the surface of an object such as a cup, T-shirt, sofa, car.
In this paper, we will discuss about what is the most different spectral reflectance in comparison with a reference spectral reflectance under various illuminants. A measure is defined based on an information criterion whose probability is derived using metameric mismatch volume. The solution of the orthogonal spectral reflectance is derived as an optimization problem maximizing the information criterion. Maximizing the information criterion implies that the two information of spectral reflectances are the most different from the view point of information theory. Experimental results of the optimization derive physical shape of the orthogonal spectral reflectance for a given spectral reflectance.
To investigate influence of light source and illuminance on Benham type subjective colors, a technique using twenty eight figures that have different arc positions is proposed. An incandescent lamp and three wavelengths fluorescent lamp were used as light sources, and subjective colors were measured. Patterns of the diagrams on hue and chroma for the two kinds of lamp are different. The difference between the light sources is clearly recognized.
The aim of this investigation is to describe the semantics of color and to give the determination of information on the basis of using light-color properties of radiant flux. The determination obtained permits to introduce reliable criteria of information separated into linked or unlinked, and also to give the formula for estimation of the spectral luminous efficiency V((lambda) ) and complementary colors in Hering theory.
It seems that everywhere you look there is some article or discussion about color management. Why all the fuss? Do I need to management my colors? We have been creating colored artifacts for a very long time and I don't think we have needed color management. So why now? Most of these discussions also refer to the ICC. What is that? These and other questions will be answered in a straightforward manner in plain English. Adobe Systems has pioneered the use of desktop computers for color work, and the author has helped Adobe pick its way down conflicting color paths with confusing road signs over the last 10 years.
The architecture used by the ICC to manage color is based on a device-independent color space called the Profile Connection Space (PCS). Each device relates its color space to that of the PCS, which allows source device profiles to be constructed without knowing the actual destination device and destination device profiles to be constructed without knowing the actual source device. The concept works well and has been widely adopted over the past several years. However, this widespread adoption has increasingly meant that profiles from various vendors will be connected in a color management system. In order for these profiles to work together, they must both implement the PCS in the same manner. Generally, this has been done well, but increasing quality expectations have shown that there are some areas in which the interoperability of profiles could be improved. The ICC has recently approved modifications to the PCS that address these issues. This paper will first describe the current ICC PCS, how it is used, and the interoperability problems that have been encountered. Next, it describes the PCS modification and shows how they improve the interoperability of ICC profiles.
ICC-color Management tools claim to give both accurate and consistent results. However, using these tools of distinct manufacturers, different results are likely to occur even if the same parameters are given. Obviously the manufacturers do not focus on the same criteria doing their optimizations, which leads to the fact that each tool has its own strengths and weaknesses. In this study, new methods for comparing ColorManagement tools were evaluated, and with these methods, ICC profiles generated by five CM tools of current leaders on the market were investigated in order to point out their weaknesses and strengths. In addition, the influence of using various ColorMatchingModules (CMM) was tested. For the generation of each ICC profile, the same measurements (ISO 12642 equals ANSI IT8. 7/3 target of Iris InkjetPrinter) were used. Since the standardized ISO 12642 file format, in which the measurement data are stored, was not accepted by each of the tools, the data-file had to be converted to proprietary formats. The investigated quality aspects were accuracy, consistency and smoothness, with ΔEab2 and ΔE943 taken as the criteria. For each aspect, performance was visualized by mapping the ΔE values to pseudo colors, giving a very intuitive view on the investigated subject. Results showed that ColorManagement tools indeed achieved good color fidelity, especially if generated as large profiles.
The objectives of the study was to compare image quality from digital photography to RGB-printer under two digital imaging workflows: legacy-based and CMS-based. Due to the difference in judging criteria, the study shows that legacy- based digital imaging workflow can produce pleasing images as good as CMS-based workflow. But ICC-based CMS out performs legacy-based workflow in matching the color appearance of the source images. This is a welcome feature in direct mail catalogs whereby printed images need to match the appearance of the merchandise closely.
This paper presents an image-dependent color mapping strategy to get the pleasant color renditions from two different approaches: (1) Mapping by Image Segmentation (MAPSEG) (2) Mapping by Histogram Specification (MAPHIST). MAPSEG is basically applied to match the device color to known original. The mappings are performed for the principal component (PC) to be matched in between the segmented areas of original and printed images. MAPHIST works to recover the faded or degraded colors for unknown original. It expands the de-saturated image gamut by Gaussian histogram specification (GHS) and makes full use of device gamut to render the pleasant images.
Most digital images can be broadly classified into scene- referred and output-referred image states. This image state concept is the basis for an image processing architecture in which captured images are converted to a standard scene- referred color encoding where appropriate scene-state algorithms are applied. A rendering transform can then be used to convert images to a standard output-referred image state for further processing before the final printing/display of the image. This architecture is facilitated by the definition of standard image color encodings known as RIMM/ROMM RGB.
We review three technological changes that will have an impact on color imaging on the Internet: bright LCD display replacing dim CRTs, compression based on foveation, and contents based image retrieval.
A multi-spectral imaging symposium was held during AICO1 consisting of invited and contributed papers. An overview of visible-spectrum imaging techniques was presented by the moderator (R. Berns), described in this paper.
The paper deals with total multispectral imaging systems assembled from a multispectral camera or scanner for capturing color images or natural scenes and a multichannel color image display for image synthesis. The aim of the multispectral technology is to reproduce an approximation to the spectral color stimuli of an original image in order to reduce color mismatches between original and reproduction for every human observer and any illuminant considered. Two system aspects are discussed in more detail: the representation of spectral data by a set of multispectral values at the interface between camera and display and the method of controlling the channels of the multichannel display to reproduce colors at least errors for every human observer. An expansion of spectral stimuli functions into a series of basis functions with weighting coefficients called multispectral values is used for the data representation at the interface. The set of basis functions is either optimized with respect to best fitting the original color stimuli or to produce least observer metamerism. It is shown that observer matched basis functions lead to smaller color errors. Best results for the control of the multichannel display are achieved with an iterative process using stochastic pattern generation. It is shown that maximum color errors for a large test set of spectral color stimuli on one side and 24 different human observers on the other are below 1,6 CIE-(Delta) E94 units if the experimental spectral characteristics of a 6-channel display are considered.
In recent years, it is required to develop a system for 3D capture of archives in museums and galleries. In visualizing of 3D object, it is important to reproduce both color and glossiness accurately. Our final goal is to construct digital archival systems in museum and Internet or virtual museum via World Wide Web. To archive our goal, we have developed the multi-spectral imaging systems to record and estimate reflectance spectra of the art paints based on principal component analysis and Wiener estimation method. In this paper, Gonio photometric imaging method is introduced for recording of 3D object. Five-band images of the object are taken under seven different illuminants angles. The set of five-band images are then analyzed on the basis of both dichromatic reflection model and Phong model to extract Gonio photometric information of the object. Prediction of reproduced images of the object under several illuminants and illumination angles is demonstrated and images that are synthesized with 3D wire frame image taken by 3D digitizer are also presented.
Estimation methods are studied for the recovery of the spectral reflectance across the visible range from the sensing at just three discrete laser wavelengths. Methods based on principal component analysis and on spline interpolation are judged based on the CIE94 color differences for some reference data sets. These include the Macbeth color checker, the OSA-UCS color charts, some artist pigments, and a collection of miscellaneous surface colors. The optimal three sampling wavelengths are also investigated. It is found that color can be estimated with average accuracy ΔE94 = 2.3 when optimal wavelengths 455 nm, 540 n, and 610 nm are used.
This paper describes a new procedure of capturing spectral images of human portraiture. The designed imaging system was calibrated directly based on real human subjects and has the capability to provide accurate spectral images of human faces, including facial skin as well as the lips, eyes, and hair, from various ethnic races. The facial spectral reflectances obtained were analyzed by principal components analysis (PCA) method. Based on the results of PCA, spectral images using both three and six wide-band spectral sampling were estimated. The reconstructed spectral images for display based on an sRGB display model are evaluated. The results have proved that this new spectral imaging procedure is successful. The results also show that three basis functions are accurate enough to estimate the spectral reflectance of human faces. The derived spectral images can be applied to color-imaging system design and analysis.
We present techniques for representing spectral images in data communications. The spectral domain of the images is represented by a low-dimensional component image set, which is used to obtain an efficient compression of the high- dimensional spectral data. The component images are compressed using a similar technique as the JPEG- and MPEG- type compressions use to subsample the chrominance channels. The spectral compression is based on Principal Component Analysis (PCA) combined with a color image transmission coding technique of chromatic channel subsampling of the component images. The component images are subsampled using 4:2:2, 4:2:0, and 4:1:1-based compressions. In addition, we extended the test for larger block sizes and larger number of component images than in the original JPEG- and MPEG- standards.
A practical and easy way to capture images of oil-paintings and estimate their spectral reflectance as a function of position was tested. For the image acquisition, a trichromatic digital camera was used in conjunction with an absorption filter producing six channels. From an a priori statistical analysis of common artist oil paints, spectral reflectance was estimated. These experiments showed that it is possible to estimate the spectral reflectance with an accuracy of average ΔE*94 of 1.7 and spectral reflectance rms error of 2.2%. Of particular interest is guidance towards the design of a universal calibration target for imaging paintings.
Two new schematic diagrams are presented here that derive from the study of the value relationships of the primary colors of RGB computer and video color. The first diagram is a 'Truth Table' that presents true-false, on-off states of the three colors of RGB so that the colors are presented in the order of their brightness values. The second diagram is a triple Venn diagram based on the perception of color. This diagram is presented as an alternative to the Venn diagrams of additive and subtractive color usually used to explain color.
In the 1940s color photography became available and within a few years, extremely popular. As people switched from black and white photographs made with the old metallic silver process to the new color films, pictures taken to record their lives and families began a slow disappearing act. The various color processes, coupled with the substrates they were printed on, affected their longevity, but many color photographs taken from the late 1950s through the 1970s, and even into the 1980s, faded not only when exposed to the light, but also when stored in the dark. Henry Wilhelm's excellent book 'The Permanence and Care of Color Photographs' documents this history in detail. Today we are making another transition in the storage of pictures and information. There are questions about the longevity of different types of digital storage, and also of the images printed by various types of inkjet printers, or by laser printers using colored toners. Very expensive and very beautiful works of art produced on Iris printers are appearing in art exhibitions. Some of these are referred to as Giclee prints and are offered on excellent papers. Artists are told the prints will last a lifetime; and if by change they don't it is only necessary to make another print. Henry Wilhelm has begun to test and rate these images for lightfastness; however, his test method was developed for examining longevity in colored photographs. It is of interest to find out how these prints will hold up in the tests required for fine art materials. Thus far companies producing digital inks and printers have not invested the time and money necessary to develop an American Society for Testing and Materials (ASTM) standard method for evaluating the lightfastness of digital prints. However, it is possible to use ASTM D 5383, Standard Practice for Visual Determination of the Lightfastness of Art Materials by Art Technologists, to pinpoint colors that will fade in a short time, even though the test is not as severe as ASTM D 4303, which is used to rate the lightfastness of artists's paint.
Over ten years ago the National Gallery in London began a program to make digital images of paintings in the collection using a colorimetric imaging system. This was to provide a permanent record of the state of paintings against which future images could be compared to determine if any changes had occurred. It quickly became apparent that such images could be used not only for scientific purposes, but also in applications where transparencies were then being used, for example as source materials for printed books and catalogues or for computer-based information systems. During the 1990s we were involved in the development of a series of digital cameras that have combined the high color accuracy of the original 'scientific' imaging system with the familiarity and portability of a medium format camera. This has culminated in the program of digitization now in progress at the National Gallery. By the middle of 2001 we will have digitized all the major paintings in the collection at a resolution of 10,000 pixels along their longest dimension and with calibrated color; we are on target to digitize the whole collection by the end of 2002. The images are available on-line within the museum for consultation and so that Gallery departments can use the images in printed publications and on the Gallery's web- site. We describe the development of the imaging systems used at National Gallery and how the research we have conducted into high-resolution accurate color imaging has developed from being a peripheral, if harmless, research activity to becoming a central part of the Gallery's information and publication strategy. Finally, we discuss some outstanding issues, such as interfacing our color management procedures with the systems used by external organizations.
In this paper, color encoding strategies for different image database applications are discussed. The color image workflow is examined in detail, and master and derivative file encoding strategies are outlined in relation to capture, maintenance, and deployment of image files. For the most common image database purposes, recommendations are given as to which type of color encoding is most suitable. Advantages and disadvantages of sensor, input-referred, output-referred, and output device specific color encodings are discussed in relation with image usage. The role of ICC color management in an image database environment is also considered.
Author(s): Peter R. Fornaro; Rudolf Gschwind; Lukas Rosenthaler; Pip Laurenson
Many contemporary art collections contain important art installations where artists have used 35 mm slides as the primary medium. The number of ours these works are on show makes it necessary to regularly change the slides due to light fading. With funding from the Henry Moore Foundation. The conservation department at Tate initiated a project to examine ways in which digital technology could be used to aid the conservation of these works. The aim of the project was to place the original slides in cold storage and explored the possibility of using digital technology to make duplicate sets for display in the gallery. The reproductions needed to be of very high quality both in terms of resolution and color management. This paper discusses the use of densitometry to calibrate both device dependent and device independent systems for digitally reproducing 35 mm slides using a scanner and a film recorder and the effect of metamery when using slide films which employ different dyes.
We present a framework to compute the distance between color distributions based on differential geometry. We investigate more detailed the case when color distributions are described as linear combinations of a set of pre-computed basic functions. Experiments in our color based image retrieval system, which were done on 1000 images from Corel image database, show the advantage of our method based on the new distance measure and color descriptor.
Historical achievements of CIE Divisions 1 Vision and Color are described and a review of current technical committee activity presented. An overview of the work of CIE Division 8 Image Technology is also presented.
In meetings just prior to the 1997 AIC Congress in Kyoto, CIE TC1-37, chaired by M. Fairchild, established the CIE 1997 Interim Colour appearance Model (Simple Version), known as CIECAM97s. CIECAM97s was formally published in 1998 in CIE publication 131. CIE TC1-37 was dissolved shortly after publication of CIECAM97s at which time, a reportership, R1- 24 held by M. Fairchild, was established to monitor ongoing developments in color appearance modeling and notify CIE Division 1 if it became necessary to form a new TC to consider revision or replacement of CIECAM97s. In the four years between AIC Congresses, there has been much activity, both by individual researchers and within the CIE, aimed at furthering our understanding of color appearance models and deriving improved models for consideration. The aim of this paper is to summarize these activities, report on the current status of CIE efforts on color appearance models, and suggest what the future might hold for CIE color appearance models.
The CIE Technical Committee TC 1-47 Hue and Lightness Dependent Correction to Industrial Colour Difference Evaluation was established in October 1998 and its aim was to improve the performance of the CIE94 color-difference formula. As a result of close collaboration between the TC members, the CIE 2000 color difference formula, CIEDE2000, was developed within two years. This paper describes the development of this formula.
There are two primary reasons that color imaging does not 'work' today. The first is that there are no broad standards that can be applied across technologies and between applications. The second is that many standards groups do not consider what is known of color and vision science as they make standards. CIE Division 8 was created to address both these problems. The plan of work and progress to date of each of the technical committees (TCs) within Division 8 are described, along with a brief description how of the TC's work will help 'make color work.'
The scope of TC 1-36 is to supplement the CIE colorimetric observers with color matching data that make a clear connection between the color specification and the underlying physiology. After careful examination of color matching data, TC 1- 36 has agreed on proposing a continuous fundamental observer with data from 10° to 1°. The 10° color matching measurements of Stiles and Burch (1959) will provide the basic data for this continuous fundamental observer. Fundamental response curves will be derived as a function of field size, taking into account the macular pigment, the ocular media and the photopigment optical densities.
A simultaneous equisection experiment using a CRT in a dark surround was performed to investigate the relationship between a uniform background and the perception of lightness. The resulting curves for different backgrounds show both exponential properties, for black and white backgrounds, and sigmoidal characteristics, for intermediate grays. The sigmoidal properties are due to crispening and roughly intersect the diagonal or identity at the lightness of the background. The simultaneous contrast is greatest for the middle gray and decreases as the device white and black points are approached. An example equation is provided to fit the observations. This equation has as its input the L* of the stimuli and the background and has two fitting parameters. The issue of lightness scaling for backgrounds is also considered and finally extensions to this research are briefly mentioned.
Psychophysical experiments were carried out for describing color appearance under 12 different sets of viewing conditions including variations of neutral backgrounds, sample sizes, textures, sample types and color attributes. The results on saturation based upon 132 colored cube samples are discussed here. It was found that observers can be trained to scale saturation with a great accuracy. There is little difference in the results for the white, gray and black backgrounds studied. Saturation is dependent upon lightness and colorfulness, i.e. an increase in saturation will increase colorfulness but with a reduction of lightness. It was also found that the saturation scale of CIECAM97s did not fit well to the visual results. An improved scale was developed.
This paper describes a new uniform color space which was derived by modifying CIECAM97s to fit available large color difference datasets including CII-Zhu, OSA, Guan, BFDB- Textile, BFDB-Paint and Munsell. Testing results show that the new color space fit the above experimental datasets better than the current best CIELAB and IPT spaces.
We recognize the outside world as a 3-D space in spite of its two-dimensional retinal image. We demonstrated a two- dimensional photograph could be perceived as a 3-D scene in a special 'dimension-up' viewing condition that a subject observed only the photograph. The color constancy was then realized in part even in the photograph and its degree increases depending on the degree of 3-D recognition. A jumbled photograph was made from an original photograph taken for a room under incandescent lamps. Either was on a wall of an experimental booth illuminated by white light. In the normal viewing condition, the subjects perceived neutral white for almost the same test stimulus whether in the original or the jumbled. In the dimension-up viewing condition, the shift of the neutral perception for the original photograph was larger than for the jumbled. This should indicate that the recognized visual space of illumination (RVSI) for the scene illuminated by incandescent lamps was constructed for the original photograph and the test stimulus was perceived as an object in the scene. The degree of the color constancy was larger in the photograph perceived as a 3-D scene than in that perceived as a mere two-dimensional scene.
We don't normally perceive the light source color in a night scene photograph even at the spot of a shining lamp, although of course we do perceive the color if we are in the corresponding real world. This different experience can be nicely explained by the concept of the recognized visual space of illumination, RVSI. We see the light source color for a shining lamp in a real world because its luminance is too high to be included within the RVSI constructed for the world. On the contrary, the luminance of the shining lamp in the photograph never goes beyond that of N10 in Munsell Value and it is easily included within the RVSI constructed for the space where the photograph is observed. The spot should appear a mere white, not a light source color. We proposed in the present paper a new method to perceive the light source color in a printed photograph. A subject used a dimension-up goggle to input only the photograph into his/her monocular eye so that he/she can perceive a 3D scene in it. The RVSI of a small brightness size was made for the scene by employing a night scene photograph and a spot in the scene was perceived as the light source color when the area had lightness 8.1 or larger in Munsell Value.
In this study, we examined the influences of color media and mode of appearance on color appearance by evaluating four attributes of color such as saturation, hue, blackness, and categorical color. CRT display and color charts were used as color stimuli both were presented in the surface-color mode as well as in the aperture-color mode. Results indicated that saturation, blackness, and categorical color names strongly depend on the mode of appearance, while the results of hue does not clearly show such a tendency.
Based on the concept of the recognized visual space of illumination an experiment was conducted to measure the color appearance of a white test patch under the conditions where it was perceived as the object color and the light source color. The apparent color was measured by the elementary color naming method when it was viewed through a green color filter at its various positions between the patch and the eye in a room illuminated by a daylight type of lamps at the illuminance 20, 100, 500 or 1,600 1x. When the filter was placed close to the patch so that only the patch was seen through the filter, it appeared very green, but the amount of the chromaticity gradually decreased as the filter was moved to closer to th eye. The color finally returned to the original white when the filter was placed directly on the eye so that the entire visual field was covered by the green filter. A bright light was added on the test patch so that the appearance may become the light source color. The prediction for the apparent color based on the RVSI was that the color does not change in spite of the change in the visual field size through the green filter because the appearance cannot be controlled by the RVSI. The prediction was confirmed.
Two sets of color appearance data were accumulated for investigating the difference between LCD projector and LCD self-luminous colors. Psychophysical experiments were conducted using magnitude estimation methods. These colors were viewed against different neutral backgrounds. These data sets were used to test the performance of five color appearance models (CIECAM97s, Hunt94, LLAB, RLAB and CIELAB together with two most recently proposed revisions of CIECAM97s: Fairchild and FC).
There are many white objects around us. For example, there are white papers, white clothes, white ceramics etc. Therefore the whiteness perception of white objects plays an important role in the impression of lighting as well as perceived color of colored objects. Whiteness perception of white objects is influenced by color temperature or chromaticity of the light sources more than the colored objects. Ayama et al. has been investigating the relationship between color temperature or chromaticity of the light sources and the whiteness perception of white objects. In this paper an objective method for quantifying whiteness perception is studied. We attempt to investigate the relationship between chroma derived from some recent color appearance models and whiteness perception. Mainly the relationship between chroma derived from CIECAM97s and whiteness perception is discussed. As a result of the investigation, it was made clear that as the chroma becomes lower the whiteness perception becomes higher and that the whiteness perception is equal if chroma is equal even if the hue varies.
The perceptual amplification of color, otherwise known as the Helmholtz-Kohlrausch effect, has been experimentally characterized for a common CRT computer monitor and the highly saturated, and pure, colors Red (255,0,0), Green (0,255,0), Blue(0,0,255), Cyan(0,255,255), Magenta(255,0,0) and Yellow(255,255,0). Twenty-four human observers conducted direct brightness adjustment, on a CRT monitor, of the original colors to match the brightness perception of corresponding equal luminance gray images. Experiments were conducted in complete darkness to eliminate the desaturating effect of flare light. Results are presented in both the monitor R, G, B color space and the 1976 CIELAB color space.
Three chromatic adaptation transforms; CMCCAT97, CMCCAT2000 and CIECAT94, and the S-LMS mixed adaptation model were tested for cross-media colour reproduction under mixed illuminants. For each model, the adaptation ratio was varied to represent the state of adaptation. Printed complex images were used as originals. A series of softcopy reproduction pairs was displayed on a CRT with a D93 white point. Observers compared the hardcopy with a given pair of softcopies simultaneously and decide which reproduction was the closer color match. The experiments were divided into three phases according to the ambient lights in the experimental room. They varied from D50 simulators, Illuminant A and Cool-white Fluorescence at similar luminance level to that of the CRT. The results clearly showed that in most cases, the adaptation ratio of 0.4 was best for all models. It was also found that the adaptation ratio was not dependent on the color temperature of the ambient light and image content. The CMCCAT2000 performed relatively well in all cases.
The visual appearance can be one of the most critical parameters affecting customer choise and, therefore, it needs to be quantifiable to ensure uniformity and reproducibility. A starting point in assessing the appearance of a consumer product might be the measurement of its colour. The description of its total appearance, however, cannot be achieved by the definition of color alone; other attributes of the material from which it is fabricated contribute to the overall appearance. The texture of a surface, for example, will cause changes in colour depending on the lighting direction; the freshness of food is judged by its overall appearance, but in a way that is much more subtle than by just its color; and novel effects such as pearlescence are added to products to enhance their attractiveness. For some products, such as cosmetics, it is not only their own appearance characteristics that are important, but also the visual effect after they have been applied to the skin, nails, hair, etc. It is clear, therefore, that the interest of industry in the measurement of appearance goes beyond simply surface color.
Faithful color reproduction of digital images requires a reliable measure to compare such images in order to evaluate the reproduction performance. The conventional methods attempt to apply the CIE Colorimetry based color difference equations, s uch as CIELAB, CMC, CIE94 and CIEDE2000, to complex images on a pixel-by-pixel basis, and calculates the overall color difference as the averaged difference of each pixel in the image. This method is simple and straightforward but often does not represent the color difference perceived by human visual system. This paper proposes a new algorithm for calculating the overall color difference between complex images. The results show that this new metric corresponds more closely to the color difference perceived by human visual system.
Whereas both the CMC color difference metric and CIE94 show a considerable dependence on chroma, our measurements of contrast sensitivity show little or no such dependence. That is, the sensitivity to spatial variations in lightness, chroma and hue do not appear to depend on chroma, at least not to an extent greater than inter-observer variability. A key difference between a contrast sensitivity experiment and a color matching experiment is that the background color is the former is of necessity the mean color of the grating, whereas the background in the latter is typically a neutral gray of specified reflectivity or luminance. Goodman hypothesized that the chroma dependence in CMC and CIE94 may result from distance from background, rather than distance from neutral; the experiments reported here test that hypothesis. Results are only preliminary: a single combination of hue and lightness was used throughout the experiments, however they indicated at least partial agreement with Goodman's hypothesis.
An experiment was carried out using CRT colors. The stimuli were selected along 24 vectors in CIELAB color space. The data was used to test various color difference formulae and uniform color spaces. The results show that there are some discrepencies between CIELAB space and experimental data. The results also suggest that there are three types of color models according to the data used to develop these models: small color-difference, large color-difference and Munsell data.
In this study, visual color difference assessements were conducted using both reflective colors which are dyed cotton fabrics with no obvious texture pattern and self-luminous colors displayed on a CRT monitor. All together, eighty-two pairs of color samples belonging to five different color centres were used. The average color difference for all pairs is about 5.0 CIELAB units. The values of the color difference for the self-luminous color pairs (ΔEself-luminous) are very close to those of the corresponding reflective color pairs (ΔEreflective), i.e., the reproduction of the reflective color pairs onto the CRT monitor was very accurate. Grey scale method was used in the visual assessment of color difference. The assessments were done using five different viewing conditions, i.e., reference viewing condition recommended by CIE (CIE Technical Report CIE 116-1995) and the other conditions which include a 3-inch gap between samples in a pair, small sized sample corresponding to 2° angle of subtend and two different background colors. In comparison with the visual color differences of the reflective pairs under the reference condition, the results obtained from the CRT color pairs are 15% smaller. Under other viewing conditions, the visual color difference of the CRT color pairs are 13 to 18% smaller than those of hte reflective color pairs. Further comparison was made using chromatic color discrimination ellipses for self-luminous and reflective colors.
An experiment was carried out to investigate the crispening effect on lightness differences. Thirty-nine neutral lightness-difference pairs were generated using CRT colors. The experiment was divided into sixteen phases according to differetn physical arrangements for each sample pair such as different sample separations, sizes, and background colors. The results show that the crispening effect does exist but is highly dependent upon the particular viewing parameters.
CIE technical committee TCl-47 was established with a goal to improve the performance of the CIE94 color-difference equation. Recent visual experiments indicated that a hue-angle dependency might exist. Four datsets focused on hue differences were used to derive a new hue-angle function. The resulting function resulted in a statistically significant improvement compared with existing color-difference equations.
Historical data of chroma scaling and hue scaling are compared and evidence is shown that we do not have a reliable basis in either case. Several data sets indicate explicitly or implicitly that the number of constant sized hue differences between unique hues as well as in the quadrants of the a*, b* diagram differs making what is commonly regarded as uniform color space inhomogeneous. This problem is also shown to affect the OSA-UCS space. A Euclidean uniform psychological or psychophysical color space appears to be impossible.
The approach and findings during the application of instrumental color quality control in industry are described, where the best tolerance formulae and tolerance limits were determined by correlating visual and instrumental evaluations. A panel of previously tested observers evaluated a collection of samples taken from production and color measurements are then compared to these assessments, according to different color difference formulae. T he formula and the limit giving the best agreement with visual evaluations were determined with two different methods. For a large variety of textile substrates, processes and market situations the CMC(2:1) formula was always the best or one of the bests, but the limits varied widely, according to the individual application. Additional shade sorting, based on the tolerance limit, was also applied in several companies. The ideal box size was also determined by comparing visual and instrumental evaluations. The application as logistical tools was established according to individual necessities.
A new color-difference data set has been produced to evaluate the lightness difference weighting functions of eight CIELAB-based formulae: CIELAB, CMC, CIE94, DCI-95, LCD97, LCD99, BFD-II and CIEDE2000. Glossy polyester fabric was dyed to prepare 220 color-difference pairs, each having mainly lightness-difference. The gray-scale method was used to assess the color-difference of each pair by an average of twenty-five color normal observers. The test results of the visual data are presented.
In many technical areas of the coloring industry, like printing, textile- and automotive industry, coloring is controlled by color measurement and color-difference evaluation. However, color-difference formulae used in practice are not well adapted to human perception. There are two formulas presented which calculate the color differences better adapted to human perception. Both formulas correct the CIE-76 formula. One of this formulas has the advantage, that it is very simple. That's why measurement results can be corrected in a simple way after measurement There is another formula given which allows including the luminance of the background in the color measurement. So far the luminance of the background was out of consideration by color measurement, although the background is very important in color vision.
In gonioapparent colors, as Lightness increases, larger ΔL*s as measured by CIE76 are visually acceptable. This study used Logit Analysis of visual observations of lightness difference to determine this dependency of ΔL* on absolute L*. A linear functionality was found. Non-linearity of this function for very dark colors observed at flop angles, where sparkle is not observed lead to a further study of dark solid colors.
Based on the psychophysical method of constant stimuli, an experiment was carried out, using CRT-generated stimuli and in CIELAB color space, to test the visual color differences in relation to colorimetric scales. The CIE Gray and Blue color centers, the most basic color and, perceptually, the most different color, respectively, were chosen, and the maximum average size of test color difference was 12 CIELAB ΔE units. The resultant visual data, procesed via probit analysis, were used to analyze the relationship between color discrimination threshold and suprathreshold color-difference preception. The equal color-difference contours, corresponding to all the visual scales, 4.0, 8.0, and 12.0 CIELAB ΔE units, were well fitted into ellipses while maintaining the orientation of the threshold one, but the shapes were not completely the same, especially at Blue center. The comparisons between visual color differences and their colorimetric counterparts, in teh CIELAB ΔE units or threshold units, show linear relations at both color centers, but the slopes were, in general, not equal to 45° and differed for all directions. Thus the suprathreshold color differences can be derived by enlarging the thresholds linearly but not uniformly, i.e. with different ratios for individual directions.
Acceptability color tolerances for CRT reproductions of real objects were measured in a psychophysical experiment. Observers visually compared colors of real objects with those of corresponding images and judged whether the differences in color between them were acceptable or not. Results showed that the distributions of the acceptability color tolerance data from the experiment were similar in shape to the MacAdam ellipses, but much larger than them.
Author(s): W. Chou; Bing Han; Guihua Cui; Bryan Rigg; Ming R. Luo
This paper describes work investigating a suitable color quality control method for metallic coatings. A set of psychological experiments was carried out based upon 50 pairs of samples. The results were used to test the performance of various color difference formulae. Different techniques were developed by optimising the weights and/or the lightness parametric factors of colour differences calculated from the four measuring angles. The results show that the new techniques give a significant improvement compared to conventional techniques.
Author(s): John Hutchings; Mark Singleton; Keith Plater; Benjamin Dias
Conventional methods of color specification demand a sample that is flat, uniformly colored, diffusely reflecting and opaque. Very many natural, processed and manufactured foods, on the other hand, are three-dimensional, irregularly shaped unevenly colored and translucent. Hence, spectrophotometers and tristimulus colorimeters can only be used for reliable and accurate color measurement in certain cases and under controlled conditions. These techniques are certainly unsuitable for specification of color patterning and other factors of total appearance in which, for example, surface texture and gloss interfere with the surface color. Hence, conventional techniques are more appropriate to food materials than to foods themselves. This paper reports investigations on the application of digital camera and screen technologies to these problems. Results indicated that accuracy sufficient for wide scale use in the food industry is obtainable. Measurement applications include the specification and automatic measurement and classification of total appearance properties of three-dimensional products. This will be applicable to specification and monitoring of fruit and vegetables within the growing, storage and marketing supply chain and to on-line monitoring. Applications to sensory panels include monitoring of color and appearance changes occurring during paneling and the development of physical reference scales based pigment chemistry changes. Digital technology will be extendable to the on-screen judging of real and virtual products as well as to the improvement of appearance archiving and communication.
The origin and selection of colors in the process industries is different depending upon how the creative process is applied and what are the capabilities of the manufacturing process. The fashion industry (clothing) with its supplier of textiles is the leader of color innovation. Color may be introduced into textile products at several stages in the manufacturing process from fiber through yarn and finally into fabric. The paint industry is divided into two major applications: automotive and trades sales. Automotive colors are selected by stylists who are in the employ of the automobile manufacturers. Trade sales paint on the other hand can be decided by paint manufactureres or by invididuals who patronize custom mixing facilities. Plastics colors are for the most part decided by the industrial designers who include color as part of the design. Graphic Arts (painting) is a burgeoning industry that uses color in image reproduction and package design. Except for text, printed material in color today has become the norm rather than an exception.
Complex refractive index of pigment violet 19 (β- modification) was determined by means of an ellipsometric method within the visible spectral range. From the known complex refractive index and the particle size of the pigment, single-scattering properties (scattering and extinction efficiency, asymmetry parameter) were calculated for vehicles of different refractive indices employing an algorithm based on Mie-theory for spherical particles. These parameters were fed into a multiple-scattering model to investigate the dependence of reflectance of a semi-infinite film on particle size and refractive index of the embedding medium. Theoretically calculated results are in reasonable agreement with corresponding experimentally determined reflectance spectra of pigment violet 19 dispersed in different solvent- and water-based resin systems.
Four samples of breakfast cereals exhibiting discontinuity, two samples of baked goods with bubbles and two translucent drinks were measured to show the degree of differences that exist between their colors measured in CIELAB and their visual equivalence to the nearest NCS atlas color. Presentation variables and the contribution of light scatter to the size of the errors were examined.
The digital revolution in the textile world has already started in a globalized manner in digital design and digital sampling, digital production and digital commerce underpinned by digital technology. This paper addresses on the present status of the digital printing technology underpinned by the digital color technology and its impact to the digital revolution process in the textile world.
A laboratory experiment was conducted to investigate the usefulness of colored LEDs in retail display window applications. Human subjects viewed two side-by-side, identical mock-up display windows, and rated their preference. Subjects showed strong preference for the colored background, compared to the white background. In general, subjects disliked the modulated intensity background. Furthermore, the use of colored light (static red and blue) on the background allowed the accent light to be decreased without sacrificing visual appeal, ability to capture attention, and ability to see displayed objects clearly. It appears from this initial laboratory study that the amount of accent light can be reduced significantly, which could provide energy savings. We believe a field study would be greatly beneficial for further confirming these results and for quantifying the total energy savings in an actual store.
An experiment was carried out to evaluate daylight simulators. The color differences of seventy wool metamers were assessed 20 times by a panel of observers under six D65 simulators. The results were used to test various color difference formulae, to evaluate the quality of these simulators and to compare the results between the present method and the CIE method which calculates a metamerism index using virtual metamers.
A metric for comparison of radiance (e.g., reflectance) spectra, based on colorimetric principles, is described. In essence, the metric is a linear approximation to the sum of a series of ΔE*ab values wherein the two spectra differ only within a single narrow wavelength band. This metric has previously been suggested as a measure of lack-of-fit between a spectral-based color model and experimental observations, as well as an optimization criterion in modeling the color behavior of color output devices.
In this paper, the application of the metric as an index of metamerism is presented. Unlike the current CIE-recommended special metameric indices, the new proposal does not require the specification of a single set of trial conditions. Further, unlike previous spectrum-based proposals, it provides results in familiar units of ΔE*ab.
Author(s): Byung-tae D. Ahn; Eun-bae M. Moon; Kyung-suk Song
Native Korean women skin colors were classified to 30 standard colors. Research was conducted using spectrophotometer to show CIE L*a*b* values. Color palette for the products of cosmetics was created. Numerical value indicates lightness and change in hue.
Computer color match prediction has shown tremendous commercial growth within the past 40 years. Until recently, very little progress had been made in improving and developing the conventional color matching methods. The present study is aimed at how can we control color matching and how should we teach color matching.
We attempted to analyze the skin color of women from the world using identical apparatuses and under identical conditions. The data was used for developing cosmetic products. The skin colors of a total of 1703 women over the world were measured to clarify the characteristics of skin color. Skin color measurement was done by using a spectrometric colorimeter. We modified the conventional erythema and melanin indices and established new respective indices which can reflect various spectral information of whole visible region. The present results were used to design new cosmetics in consideration of the optical properties of skin.
The purpose of this study was to develop a new sensitivity index connected with color matching, which makes it possible to investigate the effects of dyestuff concentration deviations in a larger part of the color space in a comprehensive manner. By the help of computer simulation and experimental design, we examined the color differences resulting from minor concentration changes in approximately 500 formulas of different compositions, altering their total concentration and the proportion of the individual dyes in them. The new sensitivity index makes it possible for the colorist to select the recipe that is the least sensitive to concentration deviations from among the computer color formulas, as well as to add a new aspect to the ranking applied in color matching so far.
The producers of sewing threads used for interior car furnishings have to comply with stringent car industry regulations. In regard to thread color the specific requirements are good color fastness to light at high temperatures and nonmetameric recipe match prediction. The use of selected 1:2 metal complex dyes is recommended for the dying of PA sewing threads. Eight dyes were tested and their dyeing properties and light fastness were evaluated in an attempt to find appropriate dyes marked by high light fastness. The light fastness of dyed samples was tested according to the standard ISO 105-B06 which specifies severe testing conditions as they appear in car interiors duing summertime and cause photo-degradation of non-fast dyes. Suitable 1:2 metallic complex dyes were selected and used for computer recipe prediction for the dying of PA 6.6 sewing threads for the car industry based on the results of experimental work.
Traditionally, in textile dyeing, metals have been used as mordants or to improve the color produced by a natural or synthetic dye. In biomedical research and clinical diagnostics gold colloids are used as sensitive signals to detect the presence of pathogens. It has been observed that when metals are finely divided, a distinct color may result that is different from the color of the metal in bulk. For example, when gold is finely divided it may appear black, ruby or purple. This can be seen in biomedical research when gold colloids are reduced to micro-particles. Bright color signals are produced by few nanometer-sized particles. Dr. William Todd, a researcher in the Department of Veterinary Science at the Louisiana State University, developed a method of dyeing fabrics with metals. By using a reagent to bond the metal particles deep into the textile fibers and actually making the metal a part of the chemistry of the fiber. The chemicals of the fabric influence the resulting color. The combination of the element itself, the size of the particle, the chemical nature of the particle and the interaction of the metal with the chemistry of the fabric determine the actual hue. By using different elements, reagents, textiles and solvents a broad range of reproducible colors and tones can be created. Metals can also be combined into alloys, which will produce a variety of colors. The students of the ISCC chapter at the Fashion Institute of Technology dyed fabric using Dr. Todd's method and created a presentation of the results. They also did a demonstration of dyeing fabrics with metals.
This study investigated the influence of various D65 simulators on visual color matching seen under five D65 simulators. These five D65 simulators were categorized by CIE No. 51 method from A to D. The gray scale rating method was used to assess the visual difference of 77 textile metamers. The instrumental color difference of each metamer was calculated using SPD of CIE illuminant D65 and real SPDs of D65 simulators. The performance factor (PF/3) was used to indicate the agreement between visual differences under five D65 simulators as well as instrumental color difference and visual difference. The observer accuracy and observer repeatability were also analyzed by PF/3 measure. The experiment results showed that the visual data obtained from category A and B D65 simulators had a good agreement in PF/3 measure. The results also indicated that better agreement between instrumental and visual color difference was obtained if the real SPDs of D65 simulator were used instead of the CIE illuminant D65 data. The general color rendering index, Ra, for each D65 simulator was calculated by CIE No. 13.3 method. However, this index was inconsistent with MI(vis) in CIE No.51 method.
It is predicted if the dye strongly absorbed the ray in shorter UV wavelength, the ray energy might destroy the dye structure. Color fastness of dyed fabric is also an important character from a viewpoint of aesthetic sense and textile end use. The purpose of this study is to investigate the relation between the blocking property of dyed fabric against UV-rays and its color fastness to light. The cotton fabrics dyed with different types of direct dyes (red, blue and yellow) and their dye solutions were respectively irradiated by xenon arc lamp. The results were as follow. Color fading of dyed fabrics depended on the structure of dyes. Even the dye having lower fastness property to light, the darker shade fabrics dyed with them were examined still remaining higher UV blocking property.
By making use of the information of the textile color blocks, reproduction of high-precision colors on fabrics that we call 'Color Image Fabrics' could be woven by Jacquard loom. Color components for each pixel on digitized original image are transformed into weaving data on textile by minimizing the color difference in CIEL*a*b* representation between the original image color and the simulated textile color.
Traditionally Computer Colorant Formulation has been implemented using a theory of radiation transfer known as Kubelka-Munk (K-M) theory. Kubelka-Munk theory allows the prediction of spectral reflectance for a mixture of components (colorants) that have been characterised by absorption K and scattering S coefficients. More recently it has been suggested that Artifical Neural Networks ANNs) may be able to provide alternative mappings between colorant concentrations and spectral reflectances and, more generally, are able to provide transforms between color spaces. This study investigates the ability of ANNs to predict spectral reflectance from colorant concentrations using a set of data measured from known mixtures of lithographic printing inks. The issue of over-training is addressed and we show that the number of hidden units in the network must be carefully selected. We show that it is difficult to train a conventional neural network to the level that matches the performance that can be achieved using the K-M theory. However, a hybrid model is proposed that may out-perform the K-M model.
A reference tristimulus colorimeter has been developed at NIST with a transmission-type silicon trap detector (1) and four temperature-controlled filter packages to realize the Commission Internationale de l'Eclairage (CIE) x(λ), y(λ) and z(λ) color matching functions (2). Instead of lamp standards, high accuracy detector standards are used for the colorimeter calibration. A detector-based calibration procedure is being suggested for tristimulus colorimeters wehre the absolute spectral responsivity of the tristimulus channels is determined. Then, color (spectral) correct and peak (amplitude) normalization are applied to minimize uncertainties caused by the imperfect realizations of the CIE functions. As a result of the corrections, the chromaticity coordinates of stable light sources with different spectral power distributions can be measured with uncertainties less than 0.0005 (k=1).
We propose an experimental setup for an imaging system using a liquid crystal tunable filter (LCTF) to implement rewritable transparent broad-band color filters with arbitrary spectral transmittances. Holding-time for each transmitting wavelength of the LCTF is controlled corresponding to a computationally designed filter function, and a time-integrated intensity image is taken with a monochrome CCD camera through the LCTF. The averaged norm error between the implemented and the expected filter functions was about 10%. The system can be applied to spectral estimation, spectral based classification and spectral based parametr estimation.
This paper describes recent developments at the National Institution of Standards and Technology in the colorimetric characterization of pearlescent coatings. The goal of this research is to develop a measurement protocol for the accurate color characterization of these coatings using an understanding of their scattering mechanism as a guide. The bi-directional reflectance of a series of samples has been measured for the visible region at incident angle of 15°, 25°, 45°, 65°, and 75° and viewing angles of +/- 80° at 5° steps. This large ensemble of measurements show general trends in the color variations with incident and viewing angles that are being used to define a preliminary subset of measuring geometries that will provide sufficient information to characterize the angle dependent color travel in pearlescent coatings.
This work forms part of an ongoing investigation to increase understanding of the sources of error associated with the measurement of diffuse reflectance by national reference instruments. Measurements of diffuse reflectance are performed at the National Physical Laboratory (NPL) via two possible routes: gonioreflectometric or integrating sphere based technologies. This work investigated the sources of anomoalies found between reflectance measurements made on different sphere based instruments, by looking at the link between the uniformity of the integrating sphere, employed, and the measured spatial distribution of light reflected from a range of samples. The results were then used to demonstrate the effect of integrating sphere design on the resulting diffuse reflectance measurement, and to comment on possible limitations to the current sphere error correction systems.
In this paper, we propose a calculation model that gives a unique metric-lightness for object-colors, which is independent of different kinds of colorimeters and also matches the actually perceived lightness. Each colorimetric result with different types of measuring geometry, for example, 0/45, d/8(SCI), and d/8(SCE), can be considerably different from others, because of the influence f the component reflected normally from the sample surface. In order to investigate the difference between the actual sensation and each output of measuring geometry, we have made a subjective experiment for many achromatic samples that are composed of various levels of reflectance and those of gloss. As a result, the measured results with d/8(SCE) are shown to be closest to human perception. However, by relating the correlation of gloss to the metric-lightness for any measuring geometry, these differences for the same sample can be decreased.
Many samples with various color and gloss grades were measured by the spectrophotometer with integrating sphere, of which light trap size was variable. Samples include white plaques, ceramic tiles, paint panels, ink-jet printings, textiles and metal surfaces. For these samples, lightness and chromaticness change with light trap size, which is relate to the elimination of surface reflection, was examined. In case of color measurement, using integrating sphere, colorimetric values are affected by the light trap size, when gloss grade of sample is different.
Modern industrial color measuring instruments are grouped into three levels according to their performance (in terms of accuracy, reproducibility and repeatability) and technical specifications: top-of-the-line, mid-range and entry-level. Due to advances in the design, manufacturing and control of the instruments, top-of-the-line specificatins are no longer achievable only for bench-top instruments: portable and on-line spectrophotometers are also available at this level. Recent advances made special features such as spectrogoniometry and double-monochromator, spectrofluorimetry - formerly encountered only in research laboratories - available in industrial instruments. Entry-level instruments have become more rugged and affordable than ever. The authors tested over 30 color measuring spectrophotometers in laboratory and industry, and found that the performance of well-maintained and well-operated instruments is within the original specficiations provided by the manufacturers.
The colorimetric control of photographic prints is an important issue of color reproduction quality. Concentration series of the three photographic dyes Yellow, Magenta and Cyan on photographic paper are very often measured without considering the optical quality of the substrate. However, this substrate, the photographic paper, produces problems for colorimetry because it emits luminenscent light from optical brighteners. Many instruments used in colorimetry are not adapted to measure such an output correctly. Here, an experimental investigation is presented which quantifies systematic shifts of spectral curves and colorimetric values of photographic paper and dyes for various measuring parameters. Several spectrophotometers equipped with different sources for irradiation such as Tungsten halogen lamp, Xenon flash lamp, D65 simulator, and two Xenon lamps with adjustable UV-filter were referenced against the results of two-monochromator spectrophotometer. In the photographic paper the largest color-difference extended to approximately 10 CIELAB-units between irradiation by a Tungsten halogen and a Xenon lamp. These differences diminished with increasing concentration of the photographic dyes, however, did not die away at the highest concentration of the dyes used. The correct colorimetric values for D65 irradiation were halfway between those for the two former lamps and near to measures received from Xenon lamp irraditoin with adjustable UV-filter. Therefore, such spectrophotometers may be used for colorimetric control of photographic prints to attain an accuracy below 3 CIELAB units, or else, two measurements with a Tungsten halogen and a Xenon lamp should be averaged.
LEDs (Light Emitting Diodes) become the most important light sources in traffic signal applications, but their use increases in other areas, e.g. indoor and outdoor signals and information boards, now also in general lighting. They become popular also as instrumental radiation sources. LEDs emit in narrow emission bands, and as every semiconductor, their optical characteristics are temperature dependent. In outdoor applications they are exposed to extreme temperatures, influencing both their absolute intensity and their chromaticity. In the present paper we investigate the spectral power distribution of different types of real LEDs, as well as the change of their spectrum with temperature. The question of measuring these spectra will be re-visited. Instruments tested fall into three categories: high-end double spectrometer, single grating instrument and array type instruments of different quality. These instruments show very different stray light rejection, band-pass, and wavelength accuracy characteristics, leading to non- negligible errors of LED chromaticity if calibration is made with incandescent lamps. Results on the influence of these factors and of spectral bandwidth and sampling rate for measuring modern LEDs will be provided. Chromaticity will be calculated based on above spectral measurements and color differences will be evaluated. This becomes a hot topic with present LED cluster construction, as LEDs mounted in a panel side by side have to agree both in chromaticity and luminous intensity to an extent that is below visual acceptability levels.
Author(s): David L. Battle; Harry J. Oana; Coleman F. Shannon
A high-performance, dual-beam spectral analyzer, the SP- 2000, has been developed based on active-pixel complementary-metal-oxide-semiconductor (CMOS) technology. Each of the two diode arrays contain 256 pixels. The small size of the analyzer allows it to be used in portable spectrophotometers. A wavelength range from 360 to 780 nm has been achieved with a wavelength resolution of 1.8 nm and a signal-to-noise ratio of 85 dB. Wavelength calibration is done separately from the instrument using eight narrow-band spectral lines. Fiber optics are used to connect the spectral analyzer with an integrating sphere so that areas as small as 3 mm can be accurately measured.
In color-related industry, reflectance spectrophotometers are one of the most popular equipment for evaluating the color quality and color difference. Currently, manufacturers claim that the measurement difference between models of spectrophotometer was lower than 0.1 CIELAB ΔE units. But in our investigation, the color difference values range from 0.5 to 0.8 CIE ΔE units, which implies that the correction models must be applied to correct such errors. In our investigation, two models were also developed, so call "Lab Model" and "R-Model". These two models only involve simple regression calculation and the results also showed significant improvement. A comprehensive comparison between those models and the previously reported models is made. The comparison involves the use of BCRA-NPL Series II titles as the calibration data and the testing is based on teh Color Curve Paper Samples.
Surface color measurements are important in a large range of industries (e.g. printing, textiles, paints and foodstuffs), and a reduction in associated uncertainties is needed to improve competitiveness in the trading of colored goods. One of the major uncertainties is due to the different between measurement scales of national laboratories. A harmonisation process co-ordinated by teh National Physical Laboratory (NPL) was set up to reduce errors in color measurements with a target such that 95% of the results should agree to within 0.5 CIELAB color difference units (ΔE*ab). Nine laboratories took part in the harmonisation process. A wide range of instrumentation was used ranging from commerically available instruments to specially developed facilities. Three of the laboratories also looked at fluorescent color measurement using the two-monochromator technique. The co-ordinator had developed techniques for determining and correcting errors in color measurements as well as a range of transfer standards for color as part of a national research program. Although not all the possible errors for the measurement of color have b ene addressed 93% of the measurements agreed to within 0.5 ΔE*ab
During the past 20 years, many changes have occurred in the color measurement systems, due to new effect pigments. Both effect pigment suppliers including the paint industry and manufacturers of color measurement systems have been affected by these changes. MERCK, as the leading manufacturer of effect pigments, has in recent years played a significant part in promoting the development of color measurement equipment. This paper reviews the development of goniochromatic color measurement systems from 1980 to state of the art. Futhermore, MERCK improvements in instrument performance and a new color measurement system will be presented.
A harmonisation process co-ordinated by the National Physical Laboratory (NPL) was set up to reduce errors in color measurements with a target such that 95% of the results should agree to within 0.5 CIELAB color difference units (ΔE*ab). Nine laboratories took part in the harmonisation; some were national laboratories and the rest commercial organizations. The techniques for determining and correcting errors in color measurements are described. Thirteen sources of error were identified, ten of which were corrected for. Although not all the possible errors for the measurement of color have been addressed 94% of the measurements agreed to within 0.5 ΔE*ab.
This paper reports on work undertaken by nine European laboratories as part of a European Commission funded research project. The project's goal was to improve harmonisation of international colorimetric scales. One objective of the exercise was to devise a means of expressing total uncertainty in color measurement. When measuring color (or indeed any physical quantity), as assessment of the uncertainty of the result is as important as the value itself. This fact, long recognized in physics, is increasingly important to any quality assured organization that relies on measurements. The approach described first determines values of the sources of spectrophotometric uncertainty, and uses a simple model to combine these into total colorimetric uncertainties. The model has been used to determine uncertainties for the follow color data: x,y, T, u', v', L*, a* and b* for the CIE 10° Standard Observer and the CIE Standard Illiminant D65 for three geometries: sepcular included, specular excluded and 0°/45°. The method is used routinely at NPL in its UKAS accredited calibration services.
Author(s): Jouni Hiltunen; J. Mutanen; Timo Jaeaeskelaeinen; Jussi P. S. Parkkinen
Accurate color measurements have become more and more important during the past few decades. This is valid not only in physical research but also in industrial production, where the importance of accurate measurements is mainly due to increased quality requirements set by the customers of various goods. The development of technology enables more and more accurate measuring systems. While the accuracy has improved one has noticed, that many unexpected factors affect the color of an object. One of these factors is the temperature of the sample. It is known that for example the reflectance of the ceramic reference tiles used for calibration of colorimeters and spectrophotometers is temperature dependent. This phenomenon is called thermochromism, which is a reversible change of color of the sample as a function of temperature. It may be noticed already at room temperature if the temperature varies few centigrades. Red and orange samples are especially sensitive to temperature variation and may cause difficulties in precise color measurements. We show, how the phenomenon is based on physical processes and not only reflects the instability of red color pigments. We derive simple formulas, which are shown to explain the experimental data. We also discuss the meaning of thermochromism for color measurements, measure the magnitude of it and propose the experimental conditions to avoid this effect.
To calibrate color meters, we use white reference plate. Common white reference plates are made with ceramic tile and have some specular components that cause some discrepancy between different geometry systems. We developed a new geometry free white reference plate that has no specular component. It will be helpful to increase the accuracy in measuring color or calibrating color meters. We want to show the properties of a new white reference plate. Our new white standard reference plate will be used for transferring the international standard of the absolute spectral diffused reflectance.
Author(s): Yan Liu; Qinghan Chen; Xianhui Bu; Pingyun Feng
The rare earth element neodymium doped yttrium aluminum garnet (Nd:YAG) is a laser crystal widely used for producing laser in the infrared range. Neodymium causes many characteristic absorption peaks in the transmittance spectrum of the Nd:YAG crystal in the visible range. The crystal appears pink under daylight and incandescent light, and colorless under fluorescent light. The colorimetric calculation results of chroma under the CIE standard fluorescent illuminant F7 do not agree with the color appearance under fluorescent light. The calculated chroma values should be near zero to agree with a colorless appearance, but it is actually 11.79 in the CIELAB color space. This failure of the colorimetric calculation is caused by the color matching functions of the CIE colorimetric observers. The color matching functions do not agree with the spectral sensitivity curves of the human eye, especially the x(λ) function does not matches the spectral sensitivity curve of the long wavelength cone photoreceptors.
Author(s): Robert T. Marcus; Peter Ruevski; David L. Battle; Kim Galloway
Personal Digital Assistants (PDAs), such as the Visor DeluxeTM by HandspringTM offer a new paradigm for the design and use of computer-driven instruments. This paper concentrates on the methods of integrating a PDA into a portable color-measuring device and on the enhanced functionality it brings to the instrument. A PDA can be programmed to give these instruments the capability to obtain reflectance data from the spectral analyzer, and translate it into spectral data, color coordinates, and color differences.
Author(s): C. Montes; Joaquin Campos; Alicia A. Pons; F. J. Heredia
Color measurement of red musts is affected by errors due to the instrument architecture. The influence of bandwidth in color coordinates errors is studied and a set of weighting functions for the color coordinates calculation, from 10 nm spectral data, is proposed.
The objective of the study was to examine the influence of the mean luminance level on the detection thresholds for red-green chromatic gratings of three different spatial frequencies. Data for chromatic sinusoidal gratings with higher mean luminance levels (within the photopic level) than those ones used in previous works were reported. The study analyzed the transition luminance between the DeVries- Rose law and the Weber law regions, and considered the validity of the constant-flux hypothesis for the three spatial frequencies tested. The results suggest that the 'flux' would not be a critical factor in the processing of chromatic gratings in the low spatial frequency range.
This paper describes the characterization of cine film, by identifying the relationship between the Status A density values of positive print film and the XYZ values of conventional colorimetry. Several approaches are tried including least-squares modeling, tetrahedral interpolation, and distance weighted interpolation. The distance weighted technique has been improved by the use of the Mahalanobis distance metric in order to perform the interpolation, and this is presented as an innovation.
As part of a larger project that is intended for self-taught color science, we developed a software tool to provide a softcopy simulation of the Munsell Book of Color under varied illuminants and for various observers. This simulation avoids setting up as ideal a particular set of pigments from which to derive spectral reflectances. The color-order database contains a reflectance function for each Munsell aim point. The aim points are the usual ones for Illuminant C and 2° Observer function. For a new illuminant and observer, each reflectance funtion is weighted by appropriate color-matching function and illuminant spectral power distribution, and integrated to produced new X, Y, and Z values. From these values, CIELAB and chromaticity coordinates are computed. Having specified atlast colors in a variety of coordinates, the program next renders them on screen as a color-navigation tool. To illustrate good practice in constructing an atlas of reflectances, the reflectance spectra from a linear series of aim points in Munsell space can be co-plotted to show the requirements for consistency of the series under illuminant and observer change.
The OSA uniform color system is a 3-D collection of color samples according to the regular rhombohedral structure in which each color is surrounded by its 12 nearest neighbors, all perceptually equally different (local uniformity). The Swedish NCS system is a 3-D collection of color samples that vary gradually in each of the three perceptual attributes. It is not clear that this arrangement implies all neighboring pairs along the respective coordinates being perceptually equally different (local uniformity). Of pairs (j,k) of interest, predicted color differences djk were calculated that have the following property. Suppose an observer selects a pair of Munsell grays (Va, Vb) that matches in size with the color difference between (j,k), then djk=|Va-Vb| is predicted by djk, on the average, with error of 0.34 in Munsell V-unit. Variation of djk in this unit was in the order of 0.22V for nearest neighboring pairs (j,k) in various cleavage planes of OSA-UCS and in the order of 0.11V for neighboring pairs (j,k) along s-coordinate and c-coordinate in sheets with fixed hue of NCS. Both were well within the prediction error range, but some systematic trends in values of djk were found.
The OSA-UCS is a color order system developed by the Optical Society of America's Committee on Uniform Color Scales. The color specification value (L,j,g) of the OSA-UCS is derived from the CIE 1964 tristimulus value (X10, Y10, Z10). However, no direct conversion algorithm from OSA-UCS to CIEXYZ has been reported. In this paper, analytic conversion algorithm from OSA-UCS to CIEXYZ has been developed, and its effectiveness is justified.
Two different transformations between the (X10, Y10, Z10) coordinates and the (LOSA, g, j) ones of the Uniform Color System of the Optical Society of America (OSA- UCS) are given related to two possible different geometrical structures. Both transformations are logarithmic functions obtained by integration of Weber fractions of ratios of suitable color stimuli. The first structure is related to the color opponency proper of the (g, j) coordinates of the OSA-UCS) system and the second one to a mixing of the (g, j) coordinates. The second transformation has a simpler and highly symmetrical structure, and the regularity of the OSA- UCS lattice is higher.
The NCS (Natural color system) is a color order system, which has been further developed by Hard and his collaborators. NCS Notation is being discussed in the international standardization. This color notation is based entirely on the perception of color as a visual and qualitataive phenomena. The ISO/TCl87 domestic committee in Japan is continuing experiment on teh validity of this NCS notation.
I studied the NCS Three Attributes Diagram and used the NCS attributes (whiteness, blackness, and chromaticity). These three NCS attritubutes can be seen in the bargraph scale, which measures the percentage of each attribute. The subjects in the experiment were requested to report their visual perception: how each color appeared in their perspective. The results of the experiments were based on the reported and calculated tests using the diagram of NCS notation.
This paper presents a flexible system for describing colors which links everyday language to color order systems. The structure based on that of the Natural Color System (NCS), has reflectance points which are defined and named. The structure is illustrated and an account is given of the processes used to establish the system of color names and modifying adjectives which identify the reference points.
Coloroid Color System has been created for people dealing with colors constructively, first of all architects and artists. Its color space is being based on experiments measuring harmony threshold, being perceptively uniform. This uniformity is the uniformity of big color differences rather than that of small color differences, it is being based on human judgement capability rather than color differentiating capability of human eye. During its elaboration we have investigated aesthetic uniformity of hues along color circles of colors with different saturation and lightness, and - in different hue planes - that of saturation and lightness sequences. During mathematical formulation of the establishment of harmony relations in Coloroid color space it has been necessary to refine aesthetic uniformity of Coloroid color space. In the interest of it we have started a new, large scale series of experiments. Within the framework of experiments we produced aesthetically uniform changing scales between distant points of Coloroid color space, possessing different lightness - partly by painting, partly by selection from a considerable number of color samples. We then investigated, which path those color scales in the color space describe.
The aim of this paper is to describe the background, the methods and the resulting color accuracy of the control process used in the production of the NCS color samples. A study of the color matching results for the NCS productions since the introduction of NCS edition 2 are presented.
Author(s): Richard J. Paltridge; Mitchell G. A. Thomson; Tim Yates; Stephen Westland
Physical measurements of surfaces' color-causing properties are typically spectroradiometric, whereas color-differencing comparisons are typically colormetric ones performed in some 3-D color space. In general, this downprojection of high-dimensional spectral data into some 3-dimensional color space incurs a loss of information, a loss that could be more critical in one color space than in another. One ecologically valid way of assessing the extent of this information loss is to determine how likely it is that a pair of surfaces which have distinctly different spectral properties would be colorimetrically indistinguishable. We describe a virtual ideal color-difference detector which uses standard color-difference metrics but has access to the absolute spectral difference in the color signals of the surface pair. Only when this ideal detector classes a surface pair as "different" yet a standard color-difference detector classes them as "same" is the pair said to be metameric. This paradigm is applied to a dataset of hyperspectral natural images using a wide variety of 3-D color spaces. The results show that, around thresholds which approximate human performance, the overal metamerism rate is very low, yet most pixels in an image will be metameric with at least one other image pixel. Thus, downprojecting spectral data onto a 3-D color space may compromise color discriminability, but is unlikely to affect color categorization performance, a finding which is in accord with evolutionary theories regarding the function of human color vision.
Color has been used symbolically in various different fields, such as Heraldry, Music, Liturgy, Alchemy, Art and Literature. In this study, we shall investigate and analyse the structures of relationships that have taken shape as symbolic systems within each specific area of analysis. We shall discuss the most significant symbolic fields and their systems of color ording, considering each one of them as a topological model based on a logic that determines the total organization, according to the scale of reciprocities applied, and the cultural context that gives it meaning.
Digital tools have impacted traditional methods employed to reproduce color images during the past decade. The shift from a purely photomechanical process in color reproduction to colorimetric reproduction offers tremendous opportunity in the graphic arts industry. But good things do not necessarily come to all in the same package. Printing processes possess different reproduction attributes: tone reproduction, gray balance and color correction requirements are as different as the ingredient sets selected for color reproduction. This paper will provide insight toward understanding advantages and limitations offered by the new digital technologies in printing, publishing and packaging. For the past five years the Clemson University Graphic Communications Department has conducted numerous color projects using the new digital colorimetric tools during the previous decade. Several approaches have been used including experimental research and typical production workflows. The use of colorimetric data in color reproduction has given an opportunity to realize real gains in color use, predictability and consistency. Meeting an image's separation and reproduction requirements for a specified printing process can involve disruption of the anticipated workflow. Understanding the printing process requirements and the fit within the specifications of a colorimetric workflow are critical to the successful adoption of a color managed workflow. The paper will also provide an insight into the issues and challenges experienced with a color managed workflow. The printing processes used include offset litho, narrow and wide-web flexography (paper, liner board, corrugated and film), screen printing (paper board and polycarbonates), and digital imaging with toner, ink and inkjet systems. A proposal for technology integration will be the focus of the presentation drawn from documented experiences in over 300 applications of color management tools. Discussion will include the structure of specifications, standards and the issues faced during the discrete steps of color image reproduction.
Evaluation of algorithms for color gamut compression was conducted using two different experimental methods. In the first, real prints in a viewing cabinet were compared side- by-side with the original images displayed on a CRT monitor. In the second, virtual prints were simulated on the monitor for comparison with the original images. The results showed that the new topographic algorithm achieved a good performance in both cases. Comparison of the two experiments, however, indicated rather different results for the other three algorithms applied to the same four test images, with the magnitude of differences between the algorithms being smaller in the case of simulated prints.
CRT displays and prints are the predominant media in color reproduction. This study investigates the color difference thresholds under the viewing conditions of cross-media color reproduction, for which the pictoral prints presented in a viewing cabinet were compared with their reproductions displayed on a CRT monitor. The results showed that the current experimental results agree reasonably well with those found in earlier studies. Observers are more tolerant of lightness changes and more sensitive to hue changes. The acceptability thresholds are image-dependent and also affected by the transformation functions used.
Multispectral imaging has been proposed to overcome the shortcomings of conventional three channel imaging. This technique uses spectral data to describe the color of each pixel, allowing for a significant increase in color accuracy. While most publications on multispectral imaging deal with different aspects of image acquisition, the output of multispectral images becomes increasingly important. This paper describes a way to use a six-primary display as a multispectral output device. Additionally to a significant increase in device gamut, the use of more than three primaries introduces additional degrees of freedom for displaying a given color. This allows to account for observer metamerism by displaying the color in such a way that the color differences are minimal for every observer. An optimization algorithm was derived that calculates optimal control values for the six channels of the projector. One important aspect of such a method is that the control values need to be constrained, because for each channel of the projector the maximum output is limited and it is also impossible to create a negative output. Using a linear programming technique such a method was found. The methods performance was evaluated using simulation. The methods dependency on the definition of the white point is discussed. Finally, it is shown that mean errors of approx. 0.5 (Delta) Eab can be achieved.
A psychophysical experiment was conducted to investigate the relationship between sharpness and preferred color of images displayed on a CRT monitor screen. Blurred versions of each of four original images were generated by convolution with a low-pass Gaussian filter. Sharpened versions of these images were created through adjustment of the image power spectrum. Each test image was decomposed into a set of spatial frequency bands, defined as octaves of the pixel sampling frequency. The Fourier power spectrum was derived, then amplitudes of selected bands were adjusted to enhance the desired spatial frequencies. The experimental results indicated that: (1) sharpness was perceived to be increased when certain spatial frequency bands were enhanced; (2) weighting the frequency bands using the standard observer's contrast sensitivity function (CSF) gives better results for particular distances; and (3) preferred image color is strongly related to image sharpness.
A new psychophysical experimental method is proposed for estimating image quality. The method comprises two steps; the first step is a 'categorical session' and the second step is a 'triplet comparison session' which is newly developed for this purpose. The triplet comparison method is developed, in order to improve the assessment accuracy and repeatability, without imposing excess observer stress during the visual assessment. Moreover, since the triplet comparison inevitably reduces the number of comparisons, experimenter can design psychophysical experiments using a higher number of samples, compared to the paired comparison method. A series of psychophysical experiments were conducted and performed. It is found that the proposed method gives reliable and stable results so far examined.
A new region growing color image segmentation algorithm is presented in this paper. This algorithm is invariant to highlights and shading. This is accomplished in two steps. First, the average pixel intensity is removed from each RGB coordinate. This transformation mitigates the effects of highlights. Next, region seeds are obtained using the Mixture of Principal Components algorithm. Each region is characterized using two parameters. The first is the distance between the region prototype and the candidate pixel. The second is the distance between the candidate pixel and its nearest neighbor in the region. The inner vector product or vector angle is used as the similarity measure which makes both of these measures shading invariant. Results on a real image illustrate the effectiveness of the method.
This paper describes practical algorithms and experimental results using the sensor correlation method. We improve the algorithms to increase the accuracy and applicability to a variety of scenes. First, we use the reciprocal scale of color temperature, called 'mired,' in order to obtain perceptually uniform illuminant classification. Second, we propose to calculate correlation values between the image color gamut and the reference illuminant gamut, rather than between the image pixels and the illuminant gamuts. Third, we introduce a new image scaling operation with an adjustable parameter to adjust overall intensity differences between images and find a good fit to the illuminant gamuts. Finally, the image processing algorithms incorporating these changes are evaluated using a real image database.
Author(s): Gary W. Meyer; Harold B. Westlund; Peter A. Walker; Joseph P. Wingard
A computer graphic system has been developed that allows a color scientist to evaluate the appearance of gonio-apparent colors. Reflection modeling software is used to define a BRDF from existing computer graphic reflection models and standard appearance measurements for gloss and metallic travel. A visualization program allows the user to examine the BRDF that results from reflection modeling. Real-time software and hardware can be employed to adjust the BRDF and display a surface with the specified reflection properties. A high quality rendering system is available to make individual pictures that incorporate complex lighting and reflection effects.
This paper describes a method for estimating a reflection model from a color image of an object taken by a multi-band CCD camera. The Torrance-Sparrow model is used for modeling light reflection on an object surface. We propose algorithms for estimating model parameters from a single image by the multi-band CCD camera. To estimate the surface roughness, we propose the use of the brightness image and the reflectance map in the neighborhood of a highlight peak point. An algorithm is presented for finding a particular solution of the surface orientation. The feasibility of the method is demonstrated in an experiment using a painted object. The estimation accuracy of the whole model is confirmed based on computer graphics images.
A new method to improve the accuracy of color transformation, using sub-divided sRGB color space, is proposed. This combines tetrahedral partition technique and linear regression model. It is found that the 3rd order coefficient matrices give acceptable result with average color difference, (Delta) Erms equals 3.31. This process is quick and simple for general use of Internet's application.
Spectral reflectance of most reflective objects such as natural objects and color hardcopy is relatively smooth and can be approximated by several numbers of principal components with high accuracy. Though the subspace spanned by those principal components represents a space in which reflective objects can exist, it dos not provide the bound in which the samples distribute. In this paper we propose to represent the gamut of reflective objects in more distinct form, i.e., as a polyhedron in the subspace spanned by several principal components. Concept of the polyhedral gamut representation and its application to calculation of metamer ensemble are described. Color-mismatch volume caused by different illuminant and/or observer for a metamer ensemble is also calculated and compared with theoretical one.
A novel color reproduction method that is independent of the viewing angle is proposed. In this method two sets of tristimulus values corresponding to the CIE 1931 and the CIE 1964 color matching functions are reproduced using a six- primary display. The digital counts of the six-primary display to reproduce a given set of six-stimulus values can be uniquely determined by using a 6 by 6 matrix which is calculated from the two color matching functions and the primary spectra of the six-primary display. In this paper we report the result of the simulation that examines the color reproduction accuracy using this method when a spectrum of the object is given. Comparing the color reproduction accuracy achieved by the 6-primary display using our method with that by a current RGB display it is verified that the proposed method can improve the accuracy.
Multi-spectral imaging systems can be used recover estimates of the spectral reflectance properties of surfaces in an image. This process can be aided by utilizing a priori knowledge of the reflectance spectra derived from linear models of surface reflectance. We use this recovery method in a simulated camera system, and investigate the effect of varying sensor characteristics and illuminants on the accuracy of the system. We also investigate the effect of quantization noise and random sensor noise on the process. Unlike other recovery methods, increasing the number of sensors in the system - and hence the number of basis functions used in the linear model - does not necessarily improve performance. We find that increasing the amount of noise increases reconstruction error and it does so to a greater extent for large sensor numbers and large sensor bandwidths. The robustness of the process to noise is improved by using illuminants that have approximately equal power across all visible wavelengths of light.
The color characterization of organic light emitting diode (OLED) display technology is a technical challenge that must be understood. This paper will present the methodology for a full-color characterization of a prototype, which uses Kodak OLED technology. The color characterization will be centered on achieving an aim D65 white point at a luminance level of approximately 100 cd/m2. Such a color characterization reveals the neutral scale and color reproduction characteristics of the OLED. This paper will present the results of software implementation techniques that enhance the overall color reproducion performance of the Kodak OLED prototype.
This paper reports on the development of a test method for the assessment of the color performance of typical consumer- type digital still cameras. The color properties investigated were color aliasing, general color reproduction, task-specific color reproduction and automatic color balance. Some typical results are presented to illustrate the types of comparisons that may be drawn.
Author(s): Berenice S. Goncalves; Alice C. Pereira; Fernando R. Pereira
This work approaches the importance of lighting in the process of chromatic categorization, selection and specification applied to the printed media. Some concepts regarding lighting are presented, such as color temperature, color appearance and color rendering index. Finally, stands out the necessity to evaluate the samples under standard lighting conditions regarding the environment where the final product will be exposed.
In perceiving objects, generally we see them in a white light situation. But, actually, there is not an absolute white, in such a manner that the different light sources have a determined kind of white, what it is known as color temperature. Even the white light may be of different kinds (different color temperature), the individual mind tends to perceive it as the same kind of white, that is to say, there is in our mind a psychological function by which we operate an integration in the perception in order to do the object perceptually invariable. On the other hand, it is a common practice in stage lighting to use color light sources. It is a well known phenomenon that a color of light produces a change in the object color perception. However, when we go to theater, we see the objects as having their real color, even if the lighting is not white. In this paper the concept of white light in stage lighting is presented, showing its possibilities of aesthetical expression.
The color science is a part of many different eduacational fields. This means that it is treated from many different aspects and according to different disciplines. It one considers the interdisciplinary features of color science and the different angles of approach and the different facets of color which exist, unexpected opportunities open up for the treatment of color in an eduation context. The purpose of this paper is to show how the color education can develop creative environments where creation, communication and exchanges of experiences between different disciplines are the central point and also to show the role of the AIC Study Group on Color Education in this matter.
The paper describes the methodology and results of a project under development, aimed at the elaboration of an interactive bibliographical database on color in all fields of application: philosophy, psychology, semiotics, education, anthropology, physical and natural sciences, biology, medicine, technology, industry, architecture and design, arts, linguistics, geography, history. The project is initially based upon an already developed bibliography, published in different journals, updated in various opportunities, and now available at the Internet, with more than 2,000 entries. The interactive database will amplify that bibliography, incorporating hyperlinks and contents (indexes, abstracts, keywords, introductions, or eventually the complete document), and devising mechanisms for information retrieval. The sources to be included are: books, doctoral dissertations, multimedia publications, reference works. The main arrangement will be chronological, but the design of the database will allow rearrangements or selections by different fields: subject, Decimal Classification System, author, language, country, publisher, etc. A further project is to develop another database, including color-specialized journals or newsletters, and articles on color published in international journals, arranged in this case by journal name and date of publication, but allowing also rearrangements or selections by author, subject and keywords.
This past fall the Center for Imaging Science initiated a distance learning option for its Masters Degree in Imaging Science. This program is identical to the local version of the degree except for th fact that students take the course at a distance. Initially, the program offered a specialization track in Color Imaging but now the program includes Remote Sensing and Digital Image Processing tracks. My course, Vision & Psychophysics, was one of the first courses to go online. The model we have used for this endeavor is an asynchronous one; students may take the courses anywhere and learn on their own schedule. Judging by the experience of the instructors and the feedback form our students, we feel that this endeavor has been a success. In this paper I will describe my experience in designing implementing, and teaching a distance-learning course. The goal is to facilitate others who may be considering teaching in this way by sharing my limited experience.
This paper makes a case for a structured use of everyday language as a means of introducing the concept of a color order system, which is seen to be of particular value to designers. A distinction is made between teaching and learning, and some of the obstacles to learning faced by design students are described. It is suggested that a step by step approach, as embodied in a system of Color Zones, could ease the learning process. An account is given of the Color Zones system, its antecedents final development, and first trials in the classroom.
This paper describes the evolution of the course 'The Psychology of Color' that I teach at the Fashion Institute of Technology. Information was synthesized from many disciplines including human biology, physics, consumer behavior, developmental psychology, cross-cultural anthropology and sociology. After initial implementation, the course went through two additional phases of refinement. The current course is an integration of research, theory and application to our everyday lives.
Visual color matching equipment designed to illustrate the principles of CIE colorimetry is described. It enables students to individually match spectrum colors, surface colors, or self-luminous displays. The use of a photometer enables quantitative results to be obtained.
Great technological advances can help us to recover communication areas that might otherwise be lost. Media competition and visual contamination frequently appear in daily communication. A notable anonymity in human relationship has emerged as a consequence of this. Educational establishments receive an overflowing number of students. Schools and students are overwhelmed by this situation. Teachers don't know their students and students usually don't know their own classmates, with all the consequences that this implies. In front of this inadequate structure of educational institutions, technology has improved the possibilities of instant answers and the dialogue between teachers and students; the unilateral exposition pronounced by teachers in front of the anonymous mass finds an alternative in multimedia systems. The present work describes Interactive Multimedia System's utilization for teaching the chromatic circle as a system of color organization. The proposed method intends to devise a theoretical and conceptual frame and its production for multimedia systems oriented to elaborate, represent, store, interact with and access to knowledge Its relevance comes from the potential contribution to build up knowledge systems that value cultural codes and at the same time make creative and motivating interactive experiences. This work concerns the realization and understanding of the chromatic circle, selection of different color systems, logical strategies for playing and studying theory and multimedia. Levels of visualization: theory, practice, developing skills, works and evaluation. Levels to study: teaching chromatic circle, multimedia supports, quality, application and linking screens, help, theory, etc; without losing the interdisciplinary nature of the work, specialist participation, and Multimedia Systems in the steps of its realization.
Author(s): Werner Sobotka; Carina Gloss; Martin Seiter
CBT - Computer Based training, an approach for designing teaching aids was tested in this project and it will be shown how this new teaching instrument can be used for teaching basic color theory and advanced color technology for the media industry. The different types of media were tested in this project and the advantages and disadvantages of CDs, DVDs, online-services tele-teaching facilities in the field of color technology will be pointed out. Examples of CDs and online-activities will be shown and a complete course outline system for different levels will be pointed out starting with apprenticeship level, high school level up to company training and college course training materials. Mainly a lifelong learning approach will be emphasized to give especially SMES (small and medium enterprises) in media industry the possibility to train their professionals properly without too much absence from the company necessary.
The color design processes of visual artists, architects, designers, and theoreticians included in this presentation reflect the practical role of color in architecture. What the color design professional brings to the architectural design team is an expertise and rich sensibility made up of a broad awareness and a finely tuned visual perception. This includes a knowledge of design and its history, expertise with industrial color materials and their methods of application, an awareness of design context and cultural identity, a background in physiology and psychology as it relates to human welfare, and an ability to problem-solve and respond creatively to design concepts with innovative ideas. The broadening of the definition of the colorists's role in architectural design provides architects, artists and designers with significant opportunities for continued professional and educational development.
Architecture is an interdisciplinary profession that combines and uses the elements of various major fields such as humanities, social and physical sciences, technology and creative arts. The main aim of architectural education is to enable students acquire the skills to create designs sufficient both aesthetically and technically. The goals of the under graduate program can be summarized as; the information transfer on subjects and problems related to the application of the profession, the acquisition of relevant skills, and information on specialist subjects. Color is one of the most important design parameters every architect has to use. Architect candidates should be equipped in the field of color just as they are in other relevant subjects. This paper deals with the significance, goals, methods and the place of color education in the undergraduate program of architectural education.
This study focuses on the ways for providing alternative color education with Web-based instruction. The Web-based color education enhances the effectiveness of learning by integrating the multi-modal features of digital color experiences. The newly developed Web-based education color is designed for applying constructivism as educational pedagogy. This study shows how the web environment can be used as an ideal learning platform for educators and students holding the frame of constructivism.
The Rainbow Solfege System is an innovative, interdisciplinary music teaching method that illustrates in living color the linear and vertical energy of melodic movement and harmonic progressions: a synthesis of color, shape, sound and language. The system is rooted in proven pedagogical practice, while providing a fresh approach to educational methodology. Rainbow Solfege is based upon principles of tertian harmony and concepts of tonality in music and is analogous to color theory and shape theory in art. The pedagogy is holistic in design involving a variety of learning modes - visual, aural and kinesthetic - and is an effective learning tool for all ages and stages. Educational uses run the gamut from teaching musical concepts and color/shape theory for very young children to applications in college level music theory and analysis courses. With consistent application, particularly in early childhood, the method has potential for increasing musical, artistic and linguistic abilities for life.
The early 20th century saw the development of the two branches of post-classical physics: quantum mechanics and relativity. After nearly a century quantum mechanics remain paradoxical and incompatible with relativity. The main feature differentiating post-classical physics from classical is the role of the observer. Classical physics describes observer independent phenomena whereas post- classical models require an observer. Observer dependence is the source of quantum paradoxes. Most attempts to resolve these paradoxes have used a highly simplistic model of observation. Interaction and observation were assumed to be functionally equivalent. This presentation will explore the possibility of using a more realistic model of observation. Colorimetry will be used as an archetypal model of observation wherein interaction and observation can be differentiated. Some of the difficulties one would encounter in deriving electromagnetic wave equations from a color space coordinate system are highly analogous to quantum paradoxes. While resolving no paradoxes, this approach may provide a fruitful new perspective on these problems, along with a unique role for colorimetry and colorimetric education in the field of theoretical physics.
Teaching color to students of architecture and design within the higher education sector is becoming more of a luxury than of core business. With increasing financial demands, reduced resources, and increasing student numbers, educators are required to think laterally to cater for change without sacrificing learning objectives. This paper raises some of the issues involved in the educative climate within one Australian university setting. Using a reflective narrative, educational objectives are defined, the implementation of new modes of 'teaching' as a means of coping with higher student numbers and reduced staffing and technical resources are described, and the outcomes in terms of student learning over an eight year period are critiqued. Institutional management policy is forcing the educator to re-evaluate the value of the traditional studio, and the intensive 'hands- on' interactive approach that traditionally is integral to such an approach. As curriculum development involves not only theory and project work, the classroom culture, the physical environment and the University and School context need to be addressed. Generic skills, in association with professional knowledge and skills, should be addressed, and therefore, opportunities for teaching a traditionally studio-based subject on-line as a computer based unit would appear to be limited. This discussion aims to pose questions, as well as reflecting upon successes and failures in this area of education within the University context. There is a need to embrace the contextual demands while ensuring that the student knowledge of color , and the joy of discovering its characteristics in practice, are not sacrificed but enhanced.
I was a Consult in important Ceramic Companies in Argentina; San Lorenzo, Acuarela, Loimar, Piu; I also made products and color developments for Losa Olavarria. This is my experience about conveying to young designer's desires of creating: investigating and showing their ideas. The 'Ceramic Designer' career doesn't exist in my country. The experience was and is: to form design groups with young people in the areas of 'Graphic Design,' 'Textile,' and 'Arts.'
Author(s): Jack A. Ladson; Laraine B. Turner; Paul Green-Armytage; Robert W. G. Hunt
We live in a world in which styles and technologies are nearly the same from place to place, but change daily. This changing global culture is unprecedented, and reinforced by emerging new technologies that affect us all. The Future of Color, examines new technologies, how they will affect the selection and promulgation of color in the near future, and their impact upon us. We examine this topic from many perspectives - technological, business and commercial. Most importantly, as we understand how our world is emerging, we can position ourselves strategically for tomorrow.
My brief for this report was to reflect on the congress from the point of view of the visual arts, architecture and design, and to say something about how I see the future of color in these fields. I will say a bit about the congress itself, a bit about some of the topics that particularly struck me, and a bit about the future - the future that seems likely and the future that I hope for.
The present position and future goals of color science and technology are reviewed under the following headings: Color vision, Color appearance, Color differences, Color measurement, Color rendering and metamerism, and Color imaging.
Aristotle said that the unexamined life is not worth living. My challenge to you is this: "Examine your life in light of what you have heard today".
Leadership is defined as the ability to motivate others towards a common goal - a guiding light. Let each one of us leave this conference being committed that we will be the guiding light to propagate color to teh ends of the Earth and beyond. Remember my challenge to you at the beginning of the conference - "Become involvedmake a difference and have the time of your life".