Application of spectral information to investigate historical materials - Detection of metameric color area in Icon images

Abstract

The spectral reflectance of Icons is estimated from RGB digital images taken by a digital camera, and it is applied to detect metameric color areas in the Icons. In this paper, two detection methods are proposed and examined by using a test chart and ten Icons painted on wooden plates. The first method is based on the definition of metamerism that two stimuli can match in color while having a disparate spectral reflectance. The second method is based on a phenomenon that the variation of the color difference between two colors is changed by replacing the illuminant if the colors are metamers to each other. The experimental results can be used to consider which parts of the Icons have been repainted as restoration treatments. Despite the necessity of further consideration and improvement, the experimental results demonstrate that the proposed methods have the basic ability to detect metameric color areas. © Springer-Verlag Berlin Heidelberg 2005.