Paul Gauguin in Brittany
Author(s):
John F. Asmus
Show Abstract
Ever since the dawn of the 20th Century there has been a universal consensus that Alphonse Mucha launched the
sensation that became known as Art Nouveau. This event was associated with the appearance of his Gismonda poster
promoting the Sarah Bernhardt play of that name in Paris in 1894. At an estate sale in 1954 a small collage bearing a
likeness of Mucha's Gismonda was offered. It had been fabricated by gluing slivers cut from sixty postage stamps to a
20cm ceramic tile. Digital computer image enhancement was applied to the collage design, initials on a walking stick
from the same estate collection, and the Mucha poster. These geometrical analyses revealed that the collage is more
detailed than the Mucha "original". This led to our hypothesis that the famous poster was a hasty photographic
plagiarism of the intricate ceramic-tile collage. Image analyses of the initials on the companion walking stick revealed
conformity with the famous enigmatic "P GO" monogram of Paul Gauguin. We conclude that Gauguin rather than
Mucha created the Gismonda composition. Historical evidence suggests that, while Gauguin was in Brittany recovering
from injuries sustained in a fistfight, Annah la Javanese stole his possessions and took them to Paris where her next
lover, Mucha, copied the collage and presented it as his original poster design.
Visible and infrared reflectance imaging spectroscopy of paintings: pigment mapping and improved infrared reflectography
Author(s):
John K. Delaney;
Jason G. Zeibel;
Mathieu Thoury;
Roy Littleton;
Kathryn M. Morales;
Michael Palmer;
E. René de la Rie
Show Abstract
Reflectance imaging spectroscopy, the collection of images in narrow spectral bands, has been developed for remote
sensing of the Earth. In this paper we present findings on the use of imaging spectroscopy to identify and map artist
pigments as well as to improve the visualization of preparatory sketches. Two novel hyperspectral cameras, one
operating from the visible to near-infrared (VNIR) and the other in the shortwave infrared (SWIR), have been used to
collect diffuse reflectance spectral image cubes on a variety of paintings. The resulting image cubes (VNIR 417 to 973
nm, 240 bands, and SWIR 970 to 1650 nm, 85 bands) were calibrated to reflectance and the resulting spectra compared
with results from a fiber optics reflectance spectrometer (350 to 2500 nm). The results show good agreement between
the spectra acquired with the hyperspectral cameras and those from the fiber reflectance spectrometer. For example, the
primary blue pigments and their distribution in Picasso's Harlequin Musician (1924) are identified from the reflectance
spectra and agree with results from X-ray fluorescence data and dispersed sample analysis. False color infrared
reflectograms, obtained from the SWIR hyperspectral images, of extensively reworked paintings such as Picasso's The
Tragedy (1903) are found to give improved visualization of changes made by the artist. These results show that
including the NIR and SWIR spectral regions along with the visible provides for a more robust identification and
mapping of artist pigments than using visible imaging spectroscopy alone.
UV-fluorescence spectroscopy for identification of varnishes in works of art: influence of the underlayer on the emission spectrum
Author(s):
Mady Elias;
Caroline Magnain;
Carlos Barthou;
Austin Nevin;
Daniela Comelli;
Gianluca Valentini
Show Abstract
The identification of varnishes may be essential for the choice of the appropriate solvent during their removal by
restorers. This recognition is obtained by UV-fluorescence emission spectroscopy with a quasi-monochromatic UVexcitation.
A new portable instrument has been developed in order to implement non-destructive, contactless and in situ
measurements, providing results in real time.
The method is applied to the analysis of a real ancient painting. The resin-based varnish, the recipe and the state of
degradation of the varnish are deduced in different locations of the painting by comparison with a database of reference
varnishes. Moreover, spectral data are compared with the Fluorescence Lifetime Imaging (FLIM) analysis, performed on
the same painting. Different areas containing the same varnish can then be localized on the whole painting. These results
show that both UV-fluorescence methods are complementary for rapid and in situ analysis of varnishes of an entire work
of art.
Nevertheless, the paint layer beneath the varnish modifies the varnish fluorescence spectrum thus complicating its
recognition. Indeed, the possible fluorescence of the binder of the paint layer or its reflectance spectrum must be taken
into account. A systematic experimental study on fresh and aged model samples made of different varnishes, pigments
and binders is presented in this work. It shows that UV-fluorescence emission spectra and diffuse reflectance spectra
must be coupled to extract the fluorescence of the single varnish. Both spectra can be recorded by the presented
instrument. A new theoretical approach is summarized in order to explain this phenomenon.
The application of visible-induced luminescence imaging to the examination of museum objects
Author(s):
G. Verri
Show Abstract
Visible-induced luminescence imaging in the near infrared range
(800-1700 nm) can play a key role in the spatial
characterization of certain historical blue pigments (principally Egyptian blue, Han blue and Han purple). All three of
these pigments show a very strong infrared emission when excited across the visible range. The setup required for this
type of measurement comprises a recording device with some sensitivity to near infrared radiation and an excitation
source in the visible range. Inexpensive and widely available excitation radiation sources that can be used for this
application include fluorescent lamps and LEDs. While visible LEDs do not usually emit infrared radiation,
commercially available fluorescent tubes may emit some stray infrared radiation. Although the presence of such stray
infrared radiation may in some cases be considered beneficial, allowing the user easily to locate the presence of the
pigments under investigation within the composition of the piece, it can be easily removed using a simple subtraction
method. This method, based on the measurement of the reflective properties of the surface under investigation in the
emission range of the luminescent pigments, is described. The emission results obtained for Egyptian blue, Han blue and
Han purple are compared to those of a set of representative historical and modern blue pigments, including manganese
blue, which was the only other pigment found to show detectable luminescence properties. Examples of the application
of visible-induced luminescence imaging to archaeological objects of the Antonine period (AD 100-200) in the
collections of the British Museum are also presented.
Use of visible and infrared reflectance and luminescence imaging spectroscopy to study illuminated manuscripts: pigment identification and visualization of underdrawings
Author(s):
Paola Ricciardi;
John K. Delaney;
Lisha Glinsman;
Mathieu Thoury;
Michelle Facini;
E. René de la Rie
Show Abstract
Site specific, in situ techniques such as X-ray fluorescence (XRF) and Raman spectroscopy are commonly used to
identify pigments on illuminated manuscripts. With both techniques, spectra are usually acquired on visually identified
sites thought to be representative of the pigments and mixtures used for the illumination. Such visual inspection may not
always ensure an adequate representation of the pigment diversity. Here we report on the application of multispectral
(MSI) visible/infrared reflectance and luminescence imaging spectroscopy, along with fiber optics reflectance
spectroscopy (FORS) to help determine and map the primary pigments in a late 14th century miniature on vellum,
attributed to Niccolo da Bologna and representing the birth of John the Baptist. XRF analyses of visually selected sites
found elements consistent with azurite, ultramarine, vermillion, lead white, "mosaic gold" and yellow earth pigments.
Visible/infrared FORS analyses confirmed these assignments and showed evidence for the use of organic dyes. The
spectral analysis of the MSI-reflectance images gave distribution maps for these pigments (i.e., regions of azurite,
ultramarine, vermillion) along with some indication of pigment layering not identified visually. The luminescence image
gave a probable map of the organic dye(s). Images acquired in the near- and shortwave-infrared (NIR and SWIR, 750 to
2400 nm) revealed preparatory sketches and illumination techniques. These results show, like those of a prior study
carried out on another 14th century Italian miniature, that the combination of low light multi-spectral imaging
spectroscopy with FORS provides improved in situ mapping and identification of pigments on illuminated manuscripts.
Double laser LIBS and micro-XRF spectroscopy applied to characterize materials coming from the Greek-Roman theater of Taormina
Author(s):
Maria Francesca Alberghina;
Rosita Barraco;
Maria Brai;
Tiziano Schillaci;
Luigi Tranchina
Show Abstract
The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown, in recent years, its
great potential for rapid qualitative analysis of materials. The possibility to implement a portable instrument that perform
LIBS analysis makes this technique particularly useful for in situ analysis in the field of cultural heritages.
The aim of this work is to compare the results, obtained by LIBS measurements with X-Ray Fluorescence (XRF) ones,
on calcareous and refractory materials coming from the Greek-Roman theater of Taormina. Calibration curves for LIBS
and XRF were obtained by measuring certified reference materials and using them as standards. LIBS measurements
were performed with a new mobile instrument Modì (Mobile Double pulse Instrument for LIBS Analysis) that use an
innovative experimental set-up, based on the use of two suitably retarded laser pulses that greatly improves the potential
of this technique for accurate quantitative analysis. XRF analyses were performed with a portable instrument ArtTAX
that use a collimated X-Ray beam equipped with a fluxing system of helium gas on the detection path to the aim to detect
the lighter elements with a good accuracy. LIBS results have shown that this technique is highly subjected to the sample
chemical and physical characteristics.
Influence of the artistic techniques on the visual appearance of complexions in art
Author(s):
Caroline Magnain;
Mady Elias;
Jean-Marc Frigerio
Show Abstract
According to the epoch and place, the artists use the same pigments to paint the faces but change their techniques
and the binders, which modify the visual appearances (color, gloss) of the works of art. Various techniques
(encaustic, tempera, oil, synthetic binder) are investigated on model samples containing the same pigments but
different binders and on a old painting. The influence of the techniques on the visual rendering is investigated
experimentally. Goniophotometry and optical coherent tomography are used to determine the surface state, the
gloss and the surface scattering. The spectrometry in the visible range allows to characterize the bulk scattering
by determining the absorption and scattering coefficients of the pigments according to the binders. A particular
oil technique, the art glaze is also studied on a real painting.
2.5D virtual reality visualisation of shearography strain data from a canvas painting
Author(s):
R. M. Groves;
A. Li;
X. Liu;
S. Hackney;
X. Peng;
W. Osten
Show Abstract
Advanced measurement techniques for the structural diagnostics of artwork are increasingly providing more complex
data that needs to be conveyed to conservators in a meaningful way. Holography and speckle interferometry based
sensors are commonly used for this application and of these shearography is quite suitable for measurements outside the
optics laboratory, due to the stability of using a common path interferometer configuration. Shearography provides noncontact
full-field displacement gradient data on surface and sub-surface defects in the form of phase maps. The display
of this data in the form of wrapped phase maps is only suitable for experienced users. A further image processing step
generates unwrapped phase maps, which in an engineering environment are generally colour coded for display. For
artwork measurement applications, the colour variation of the painting itself is important reference for the conservator to
locate defect locations. In this manuscript the displacement gradient data is presented as false height on the flat painting
surface. A virtual reality viewer, freely downloadable from the internet, is used to display the data and allow the user to
interact with it by rotating the object in virtual space. The effect is rather similar to viewing a raked light photograph,
however with the advantage of remote or online viewing.
Application of graphically oriented programming to imaging of structure deterioration of historic glass by optical coherence tomography
Author(s):
Marcin Sylwestrzak;
Ewa A. Kwiatkowska;
Pawel Karaszkiewicz;
Magdalena Iwanicka;
Piotr Targowski
Show Abstract
Optical Coherence Tomography (OCT) is an interferometric method utilising light of low temporal coherence for noninvasive
structural imaging of objects weakly absorbing and scattering light. In this contribution, using various examples
of images of objects made of glass affected by the atmospheric corrosion and/or by crizzling, we demonstrate a software
developed in our laboratory specifically for 3D OCT imaging of samples with a fine structure. For this task we employed
the OpenGL platform (Open Graphics Library), an Application Programming Interface (API) for writing applications
dedicated to interactive 3D computer graphics. In our application we have utilized texture rendering with a modulation of
transparency and a colour as a function of elevation.
Application of optical techniques in documentation and identification of archaeological rests: the case study of the Roman bronze rest found in Lucentum
Author(s):
L. Granero;
F. Diaz;
R. Dominguez;
J. Hervás;
S. Simón;
E. Pérez
Show Abstract
In this paper it will be presented a case study of the optical technologies applicated to archaeology. This case study is
centered in the main actions executed on an extraordinary rest appeared in the excavations of the Roman forum of
Lucentum (Alicante, Spain) in 2005. This rest is a fragment of a bronze sculpture, and is catalogued as a Unicum (that is,
a sample that presents some singular elements with no comparison with other samples, in this case of the Roman Art).
That sample represents the only part that is conserved so far of that statue. This paper will explain briefly the main 3D
digitizing systems and, after that, will focus in the process of identification and documentation of the rest. In particular, it
will be widely described the 3D digitizing process of the rest and the post-processing of the information obtained on it,
showing the main steps of the work and the results obtained, used subsequently in other processes.
Terahertz metrology of tree rings for dendrochronology and cultural heritage applications
Author(s):
J. B. Jackson;
J. Labaune;
G. Mourou;
I. Duling;
C. Lavier;
M. Menu
Show Abstract
Terahertz imaging will be presented as a novel method of nondestructively measuring otherwise inaccessible tree-rings
for the purpose of dendrochronologically cross-dating cultural heritage artifacts. Wood specimens were measured using
time-domain terahertz pulse reflectometry. Two-dimensional images of tree-rings were generated through analysis of
both time- and frequency-domain terahertz signals, which changed proportionally to the variations in wood density.
Terahertz pulse separation enabled wood specimens with at least two layers of coatings (primer and/or paint) to be
measured and the terahertz images were quantitatively compared to the optical photographs of related, uncoated
specimen. Tree-ring series and timelines were obtained for each terahertz image with respect to the source (reference)
ring series. Short ring width blocks were aligned to the reference series and combined to create an extended timeline for
each terahertz image. It was determined that while spatial resolution may be improved with analysis at high frequencies,
the lower signal to noise reduces the precision of the ring measurement. Constructing longer timelines from ring blocks,
significantly improves the overall quality of a match.
Terahertz imaging systems: a non-invasive technique for the analysis of paintings
Author(s):
K. Fukunaga;
I. Hosako;
I. N. Duling III;
M. Picollo
Show Abstract
Terahertz (THz) imaging is an emerging technique for non-invasive analysis. Since THz waves can penetrate opaque
materials, various imaging systems that use THz waves have been developed to detect, for instance, concealed weapons,
illegal drugs, and defects in polymer products. The absorption of THz waves by water is extremely strong, and hence,
THz waves can be used to monitor the water content in various objects.
THz imaging can be performed either by transmission or by reflection of THz waves. In particular, time domain
reflection imaging uses THz pulses that propagate in specimens, and in this technique, pulses reflected from the surface
and from the internal boundaries of the specimen are detected. In general, the internal structure is observed in crosssectional
images obtained using micro-specimens taken from the work that is being analysed. On the other hand, in THz
time-domain imaging, a map of the layer of interest can be easily obtained without collecting any samples. When realtime
imaging is required, for example, in the investigation of the effect of a solvent or during the monitoring of water
content, a THz camera can be used.
The first application of THz time-domain imaging in the analysis of a historical tempera masterpiece was performed on
the panel painting Polittico di Badia by Giotto, of the permanent collection of the Uffizi Gallery. The results of that
analysis revealed that the work is composed of two layers of gypsum, with a canvas between these layers. In the paint
layer, gold foils covered by paint were clearly observed, and the consumption or ageing of gold could be estimated by
noting the amount of reflection.
These results prove that THz imaging can yield useful information for conservation and restoration purposes.
Multi-sensor evaluation of a wooden panel painting using terahertz imaging and shearography
Author(s):
Roger M. Groves;
Boris Pradarutti;
Eleni Kouloumpi;
Wolfgang Osten;
Gunther Notni
Show Abstract
Cultural heritage objects are increasingly being investigated using advanced non-destructive optical measurement
techniques. Holographic and speckle interferometry based instrumentation allow dimensional measurement of
objects at the tens of nanometer scale. For the structural diagnostics of artwork, double-exposure techniques are
often used to locate defects, delaminations, voids and other structural features. Shearography is a speckle
interferometry configuration that uses a close-to-common-path shearing interferometer configuration to give a direct
sensitivity to displacement gradient at the object surface. This configuration is particularly useful for measurements
outside the optical laboratory, as the stability requirements are much reduced compared with holography techniques.
Terahertz imaging is a new category of sensor, used to investigate materials using electromagnetic radiation in the
0.1 to 10 THz frequency range. At these frequencies many materials become semi-transparent, so bulk structural
diagnostics can be performed. Typically terahertz imaging is performed using a scanning pixel, or multi-pixel,
sensor. In this manuscript shearography is first used to identify areas of interest of possible structural anomalies in
the artwork. These regions of interest are then studied in more detail using the terahertz imaging instrument.
Together the two instruments provide an analysis of both the surface and bulk structural features. The approach is
demonstrated experimentally using a wooden panel painting.
Picosecond laser ablation system with process control by optical coherence tomography
Author(s):
Piotr Targowski;
Roman Ostrowski;
Jan Marczak;
Marcin Sylwestrzak;
Ewa A. Kwiatkowska
Show Abstract
In this contribution we describe an apparatus for precise laser ablation of delicate layers, like varnish on pictures. This
specific case is very demanding. First of all any changes in colour of remaining varnish layer as well as underneath paint
layers are unacceptable. This effect may be induced photochemically or thermically. In the first case strong absorption of
the radiation used will eliminate its influence on underlying strata. The thermal effect is limited to so called heat affected
zone (HAZ). In addition to colour change, a mechanical damage caused by overheating of the structure adjacent to
ablated region should be considered also. All kinds of treads must be carefully eliminated in order to make laser ablation
of varnish commonly accepted alternative to chemical and/or mechanical treatments [1].
Since the varnish ablation process is obviously irreversible its effective monitoring is very important to make it safe and
trusted. As we showed previously [2-6] optical coherence tomography (OCT) originated from medicine diagnostic method
for examination and imaging of cross-sections of weakly absorbing objects can be used for this task. OCT utilises infrared
light for non-invasive structure examination and has been under consideration for the examining of objects of art since 2004
[7-10]. In this case the in-depth (axial) resolution is obtained by means of interference of light of high spatial (to ensure
sensitivity) and very low temporal coherence (to ensure high axial resolution). In practice, IR sources of bandwidths from
25 to 150 nm are utilised. Resolutions obtained range from 15 down to 2 μm in the media of refracting index equal 1.5.
In this contribution we expand application of OCT to space resolved determination of ablation rates, separately for every
point of examined area. Such data help in better understanding of the ablation process, fine tuning the laser and finally
permit increase of the safety of the ablation process.
Fourier domain optical coherence tomography for high-precision profilometry
Author(s):
Samuel Lawman;
Haida Liang
Show Abstract
A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable of profilometry with two
orders of magnitude better accuracy than the axial imaging resolution of the system. High precision OCT profilometry
not only achieves similar accuracy as commercial white light interferometry based profilometers but is also capable of
profilometry on complex subsurface structures with multiple interfaces of low reflectance. An accuracy of 55nm was
achieved with a ThorLabs SROCT on a lab bench without special
anti-vibration devices. This technique has the potential
for a range of applications, such as high precision refractive index measurements and simultaneous dynamic monitoring
of the interface structure of a drying varnish and the substrate.
Laser induced breakdown spectroscopy (LIBS) applied to stratigrafic elemental analysis and optical coherence tomography (OCT) to damage determination of cultural heritage Brazilian coins
Author(s):
Marcello M. Amaral;
Marcus P. Raele;
Anderson Z. de Freitas;
Guilherme S. Zahn;
Ricardo E. Samad;
Nilson D. Vieira Jr.;
Luiz V. G. Tarelho
Show Abstract
This work presents a compositional characterization of 1939's Thousand "Réis" and 1945's One "Cruzeiro" Brazilian
coins, forged on aluminum bronze alloy.
The coins were irradiated by a Q-switched Nd:YAG laser with 4 ns pulse width and energy of 25mJ emitting at 1064nm
reaching 3.1010Wcm-2 (assured condition for stoichiometric ablation), forming a plasma in a small fraction of the coin. Plasma emission was collected by an optical fiber system connected to an Echelle spectrometer. The capability of LIBS
to remove small fraction of material was exploited and the coins were analyzed ablating layer by layer from patina to the
bulk.
The experimental conditions to assure reproductivity were determined by evaluation of three plasma paramethers:
ionization temperature using Saha-Boltzmann plot, excitation temperature using Boltzmann plot, plasma density using
Saha-Boltzmann plot and Stark broadening.
The Calibration-Free LIBS technique was applied to both coins and the analytical determination of elemental
composition was employed. In order to confirm the Edict Law elemental composition the results were corroborated by
Neutron Activation Analysis (NAA). In both cases the results determined by CF-LIBS agreed to with the Edict Law and
NAA determination. Besides the major components for the bronze alloy some other impurities were observed.
Finally, in order to determine the coin damage made by the laser, the OCT (Optical Coherence Tomography) technique
was used. After tree pulses of laser 54μg of coin material were removed reaching 120μm in depth.
Study of varnish layers with optical coherence tomography in both visible and infrared domains
Author(s):
Gaël Latour;
Gaëlle Georges;
Laure Siozade;
Carole Deumié;
Jean-Philippe Echard
Show Abstract
Optical Coherence Tomography (OCT) is an attractive technique to study works of art because it allows non-destructive
and contactless analysis. In the case of musical instruments, the study of wood finishes could give interesting
information as the thicknesses of the layers, the number of layers and the presence of fillers. A time-domain full-field
OCT, achieving high resolution, is used in both visible and near infrared ranges to characterize semi-transparent layers
containing scattering particles as charged varnish layers. We present OCT measurements on wood varnished with
different coatings. We show that the detection of pigment particles is dependent of the spectral range and that both
spectral domains allow to reach micrometer-scale spatial resolutions.
Automated full-3D shape measurement of cultural heritage objects
Author(s):
Robert Sitnik;
Maciej Karaszewski;
Wojciech Zaluski;
Pawel Bolewicki
Show Abstract
In this paper a fully automated 3D shape measurement system is presented. It consists of rotary stage for cultural heritage
objects placement, vertical linear stage with mounted robot arm (with six degrees of freedom) and structured light
measurement set-up mounted to its head. All these manipulation devices are automatically controlled by collision
detection and next-best-view calculation modules. The goal of whole system is to automatically (without any user
attention) and rapidly (from days and weeks to hours) measure whole object. Measurement head is automatically
calibrated by the system and its possible working volume starts from centimeters and ends up to one meter. We present
some measurement results with different working scenarios along with discussion about its possible applications.
3D synchrotron x-ray microtomography of paint samples
Author(s):
Ester S. B. Ferreira;
Jaap J. Boon;
Jerre van der Horst;
Nadim C. Scherrer;
Federica Marone;
Marco Stampanoni
Show Abstract
Synchrotron based X-ray microtomography is a novel way to examine paint samples. The three
dimensional distribution of pigment particles, binding media and their deterioration products as well as
other features such as voids, are made visible in their original context through a computing
environment without the need of physical sectioning. This avoids manipulation related artefacts.
Experiments on paint chips (approximately 500 micron wide) were done on the TOMCAT beam line
(TOmographic Microscopy and Coherent rAdiology experimenTs) at the Paul Scherrer Institute in
Villigen, CH, using an x-ray energy of up to 40 keV. The x-ray absorption images are obtained at a
resolution of 350 nm. The 3D dataset was analysed using the commercial 3D imaging software Avizo
5.1. Through this process, virtual sections of the paint sample can be obtained in any orientation.
One of the topics currently under research are the ground layers of paintings by Cuno Amiet (1868-
1961), one of the most important Swiss painters of classical modernism, whose early work is currently
the focus of research at the Swiss Institute for Art Research (SIK-ISEA). This technique gives access
to information such as sample surface morphology, porosity, particle size distribution and even particle
identification. In the case of calcium carbonate grounds for example, features like microfossils present
in natural chalks, can be reconstructed and their species identified, thus potentially providing
information towards the mineral origin. One further elegant feature of this technique is that a target
section can be selected within the 3D data set, before exposing it to obtain chemical data. Virtual
sections can then be compared with cross sections of the same samples made in the traditional way.
NIR confocal microscopy for painting diagnostics
Author(s):
C. Daffara;
R. Fontana;
L. Pezzati
Show Abstract
We designed and built a simple fiber-optic confocal laser-scanning interference microscope, operating in the near
infrared (NIR), for the analysis of paintings. We applied this instrument to the non-invasive optical sectioning of the
paint layers. The device was tested on both laboratory samples and ancient paintings. The preliminary results show that
optical sections obtained by NIR confocal microscopy are comparable to those recorded with well known optical
coherence tomography and a few examples of application are presented.
Comparison of carved panels from two Irish high crosses using laser scans
Author(s):
Thierry Daubos;
Dáibhí Ó Cróinín
Show Abstract
We present the results we obtained in comparing several carved panels from two high crosses. In this study, which was
carried out as part of the RTE Cork TV program "Secrets of the Stones", we compared three panels of the Cross of the
Scriptures from the Clonmacnois monastic site, Co. Offaly with similar panels from the Cross of Durrow, located in the
grounds of St Columba monastery, Co. Offaly. The purpose of the study was to decide whether these high crosses, which
both date back to the ninth century, could have been carved by the same Celtic artist. The Cross of the Scriptures was
scanned in August 2008 using our Polhemus FastSCAN handheld laser scanner, while the Cross of Durrow was surveyed
in May 2008 by the Germany based, ArcTron 3D company, commissioned by the Offaly County Council. Using the data
from the 3D scans, details of each panel were enhanced using a wavelet filtering technique and a false colour image of
the depth field was computed for each panel. These images were then used as textures and applied back onto the 3D
models. This process allowed for expert historians to later on evaluate, by looking and manipulating the textured 3D
models, the hypothesis that the panels were carved by the same person.
Dual scale structural health monitoring system combining FBG sensors and laser scanning
Author(s):
Hugo F. Lima;
M. Fátima Domingues;
Rogério N. Nogueira;
Paulo André;
João L. Pinto
Show Abstract
This work reports a case study of a structural health monitoring (SHM) system combining large and micro scale
measurements installed in a 16th Century Church in Aveiro. This dual scale SHM system relies on a network of 24 fibre
Bragg grating (FBG) sensors to perform micro scale, high resolution displacement and temperature measurements in
several key points of the structure, while the large scale measurements are ensured by a scanning laser range finder. The
results demonstrate that the developed systems allow adequate monitoring of the evolution of deformation in buildings,
in different scales, keeping the visual impact in the structure reduced to a minimum and contributing for the
implementation of best practices for rehabilitation of historic and cultural heritage.
LIBS identification of pigments from Aula Leopoldina vault
Author(s):
R. Ostrowski;
W. Skrzeczanowski;
J. Marczak;
A. Sarzynski
Show Abstract
Aula Leopoldina is the most representative, baroque hall in Wroclaw University. In 2008, LIBS measurements of
paintings layers of Aula vault were done. LIBS spectra permitted identification of mineral pigments used for specific
colors of painting layers. This identification could not be unambiguous in each case since simultaneous occurrence of
elements that could be components of different pigments of the same color was observed in some samples. For example,
in some red samples the presence of aluminum and iron was stated, and hence red ochre or Mars red could be used as a
pigment. In other samples the cinnabar can be additionally responsible for red color. Similar problems were observed in
case of blue pigments, where existence of copper may show that azurite was used, but the presence of aluminum,
sodium, silicon and iron can point to application of ultramarine, Egyptian or Prussian blues. The greatest difficulties
occurred during identification of white pigments. Because of presence of barium, zinc, lead and titanium, the potential
pigments might be lithopone, barite, zinc white, lead white or titanium white. Final choice of the pigment is determined
by the time of last renovation and this points out that the zinc white was used.
Analysis of the European lacquer technique and technology of polychromed wooden decoration of Chinese room in Wilanow Palace in Warsaw
Author(s):
Irmina Zadrozna;
Anna Guzowska;
Elzbieta Jezewska
Show Abstract
A well preserved wooden paneling decoration of one of the rooms adhering to the King's Jan III bedroom in Wilanow
Palace is a unique example of European lacquerwork attributed to famous 18th century craft workshop of Martin Schnell.
This decorative technique is a method of applying many layers of clear or colored composition of resins available in
Europe to especially prepared ground layer. The paper summarizes the results of original painting materials identification
as well as original and late layers stratigraphy. Under certainly not original parts of polychromy there were other colors
found. It has been discovered also that some parts of the wooden paneling was removed and replaced with copies painted
in a different technique. The 3D scanner and produced orthophotoplans allowed full documentation of the state of
preservation of the whole room. The paint samples of which stratigraphic cross-sections were made have been analysed
with SEM-EDS technique and ultraviolet fluorescence microscopy. Application of the most advanced analysis
techniques like Gas Chromatography (GC/MS) and Fourier-Transform infrared spectroscopy (FTIR) allowed the most
exact identification of binding media.
Conservation of wooden art works and laser cleaning
Author(s):
A. Koss;
M. Lubryczynska;
J. Czernichowska;
I. Uchman-Laskowska;
K. Chmielewski;
M. Mazur;
A. Markowska;
J. Marczak;
M. Strzelec
Show Abstract
Laser cleaning technique has been thoroughly compared to traditional chemical and mechanical procedures in the several
case studies of wooden artworks, particularly when conventional cleaning tests showed that none of the methods known
to experienced restorers met all the requirements. Laser cleaning tool, included into conservation projects, appeared to be
very successful in the removal of old overpaintings, dirt clusters in deep artworks fractures and hollows as well as
removal of sootiness formed by mixture of soot, wax, stearin and dust from coloured polychrome. Moreover, laser
cleaning appeared to be much faster and safer for original wooden artwork substrates, especially in deeper fragments of
sculptured areas. Four case studies of different historical objects with wood as an original substrate material will be
presented. In all cases, conservation treatments followed detailed structural stratigraphy of layers and identification of
materials. For comparison, paper includes also some citations from authors earlier published works1-2.
Set of advanced laser cleaning heads and systems
Author(s):
Jan Marczak;
Roman Ostrowski;
Antoni Rycyk;
Marek Strzelec
Show Abstract
Paper presents three developments of laser systems aimed at more safe and efficient cleaning of paper and parchment,
paintings and metal artworks. Short introduction and scope of our work are included in the first paragraph. In the
following sections are presented in details:
- picosecond, diode pumped Nd:YAG laser system with computer controlled manipulation table and proposed "online"
cleaning diagnostic systems for cleaning of paper, parchment and paintings,
- ReNOVALasErb laser cleaning system (2.94 μm) with narrowed width of output pulses for cleaning of paintings,
- generator-amplifier Nd:YAG laser configuration aimed at temporal and amplitude shaping of output Q-switched
laser pulses for cleaning of metal artworks.
In-depth assessment of modifications induced during the laser cleaning of modern paintings
Author(s):
Alexandros Selimis;
Panagiota Vounisiou;
George J. Tserevelakis;
Kristalia Melessanaki;
Paraskevi Pouli;
George Filippidis;
Costas Beltsios;
Savas Georgiou;
Costas Fotakis
Show Abstract
A critical challenge for the broader implementation of laser cleaning interventions in
modern paintings is the assessment of the extent of any photochemical or structural
modifications induced in the original substrate following laser irradiation. For this reason, we
investigate several polymeric materials (PMMA, Paraloid B72) doped with aromatic
photosensitisers (PhenI, POPOP) of known photochemistry, coated with uniform layers of
acrylics of different thicknesses to simulate real case scenarios. Following laser irradiation, a
variety of spectroscopic techniques LIF, MPEF are employed for the in depth monitoring of
any photochemical and structural modifications induced in the bulk material.
Imaging data integration for painting diagnostics
Author(s):
C. Daffara;
D. Ambrosini;
R. Di Biase;
R. Fontana;
D. Paoletti;
L. Pezzati;
S. Rossi
Show Abstract
In the field of art conservation non-invasive techniques based on imaging in different spectral regions are widely used for
investigation of paintings. Using radiation beyond the visible range, different characteristics of the inspected artwork
may be revealed according to the bandwidth acquired. Beyond the traditional diagnostic methods, such as reflectography,
thermography, selective multi-spectral analysis in the near-infrared region has been recently demonstrated to be a
promising tool for investigating pictorial layers. In this work we present the results of a multidisciplinary collaboration
among two research institutes and the Accademia Galleries of Venice concerning an integrated approach for multi-view
and multi-spectral imaging data analysis for the diagnostics of paintings. In order to perform this integrated analysis, a
graphical user interface with options such as image adjustment, overlaying and transparency variation was designed. The
effectiveness of this integrated approach is recognized by the operators in the field of conservation that may thus have at
their disposal the complete set of information spanning the different characteristics of the object under investigation.
Data integration provides a multi-layered and multi-spectral representation of the painting that yields a comprehensive
analysis, confirms the anomalies individuation and reduces the ambiguity of information coming from a single diagnostic
method.
X-ray CT imaging as a scientific tool to study the capillary water absorption in sedimentary rocks used in cultural heritages
Author(s):
M. F. Alberghina;
R. Barraco;
M. Brai;
A. Lo Casto;
A. Mazzocchio;
T. Schillaci
Show Abstract
This paper proposes the X-Ray CT imaging as appropriate tool for investigating the capillary water absorption in
sedimentary rocks. This technique, in fact, provides information useful for deeping the knowledge about of the porosity
and the kinetics of the water capillary absorption in porous materials. The possibility to improve in non invasive manner,
the understanding of this phenomenon, constitutes a fundamental aspect to take actions in the restoration and
conservation of lapideous artifact and monuments from cultural heritages. The investigated sedimentary rocks come
from different Sicilian quarries and were used for the building of the Greek temples in the archaeological areas of
Agrigento, Selinunte and in the baroque monuments of the Val di Noto area. The image acquisition was carried out at
different times after contact with water. The wetting front progression along the height of the sample was evaluated on
the basis of the estimated CT attenuation value maps. An average of the CT attenuation values measured by the ROI
(Region of Interest) was used to evaluate the mean height of the wetting front, with different CT scans at fixed time
intervals after sample wetting, in order to describe the dynamic behaviour of the imbibition process. CT imaging results
have shown that the water absorption is highly subject to the sample porous morphology.
Noninvasive conoscopic holography-based device for artworks surface acquisition
Author(s):
P. Carcagnì;
E. Cavallo;
A. Della Patria;
G. Gianfrate;
L. Pezzati;
R. Piccolo;
P. Pingi
Show Abstract
Surface topography is very important for many applications. Today the most used techniques on artworks and stone artifacts
require long acquisition times and invasive interventions. For this reason, here a non-contact device improved in portability
is described. It can acquire wide areas in short times, so it is suitable for topography reconstruction with spatial resolution
of some tens of micrometers.
The starting point is a commercial conoscopic probe, the Optimet Conoline, that is able to reconstruct the depth profile
of a surface line probed by a built-in laser. Its accuracy and acquisition speed are as high as to return wide measured areas
in short times; its resolution permits fine details reproduction. Low interference with the artwork, high portability and low
response to environmental noise are the ingredients for the instrumental setup.