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Proceedings Paper

Study of chromatic variations between metameres by varying the lighting in the painting "Boy in a turban holding a nosegay" by Michiel Sweerts
Author(s): D. Vázquez; J. Muñoz de Luna; A. Alvarez; A. Sánchez; U. Sedano
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Paper Abstract

When artificially lighting a restored painting, it is important to ensure consistency in the visual perception of original and restored areas. The current paper has worked out how chromatic difference varies between restored and original areas when modifying the lighting source. In colorimetry, metamerism is the matching of apparent color of objects with different spectral reflectance. The color of a surface is the value resulting from the product of the spectral reflectance curve of the material and the spectral emittance curve of the lighting source casting light on it. As a result, the color of surfaces depends on the lighting source used to illuminate them. This paper describes the work carried out to study the color difference between original and restored metameric areas of a painting with some chromatic reintegrated areas under different light sources. Firstly, based on an ultraviolet photograph from the painting, the areas with chromatic reintegration were identified. Secondly, using a PR-655 SpectraScan spectroradiometer as well as a calibrated lighting source and measuring geometry 0°/45°, the spectral reflectance was measured at four points of the same apparent color both next to original painting and in chromatic reintegrated areas. Finally, colorimetric calculations for a 2° CIE pattern observer were performed by using spectral measurements. The color difference between the original and the restored areas was estimated under different CIE pattern illuminants by using the CIE L*a*b color space.

Paper Details

Date Published: 18 December 2012
PDF: 5 pages
Proc. SPIE 8550, Optical Systems Design 2012, 855035 (18 December 2012); doi: 10.1117/12.999506
Show Author Affiliations
D. Vázquez, Univ. Complutense de Madrid (Spain)
J. Muñoz de Luna, Univ. Complutense de Madrid (Spain)
A. Alvarez, Univ. Complutense de Madrid (Spain)
A. Sánchez, Museo Thyssen–Bornemisza (Spain)
U. Sedano, Museo Thyssen–Bornemisza (Spain)

Published in SPIE Proceedings Vol. 8550:
Optical Systems Design 2012
Laurent Mazuray; Daniel G. Smith; Jean-Luc M. Tissot; Tina E. Kidger; Frank Wyrowski; Stuart David; Rolf Wartmann; Jeffrey M. Raynor; Andrew P. Wood; Pablo Benítez; Andreas Erdmann; Marta C. de la Fuente, Editor(s)

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