A technique for detecting metameric color areas for the investigation of historical materials

Abstract

The spectral reflectance of icons is measured using a measurement system developed in our previous study, and it is applied to detect metameric color areas in the icons. In this paper, a technique for detecting metameric color areas is proposed and examined by using a test chart and ten icons painted on wooden plates. In the proposed technique, a coefficient showing the degree of metamerism is proposed; based on the definition of metamerism whereby two stimuli can match in color while having different spectral reflectance functions. The experimental results can then be used to consider which parts of the icons have previously been repainted as restoration treatments. Despite the necessity of further consideration using certain chemical analyses and so on to conclude whether or not the experimental results are reliable, they demonstrate that the proposed technique has the basic ability to detect metameric color areas.

Multispectral and hyperspectral imaging technologies in conservation: current research and potential applications

“…Moreover, the VASARI system, while integrating a set of filters, cannot really be described as multispectral because the multispectral information has only been used for accurate calibration and direct mapping to a standard CIE 6 color space. This was pointed out by Imai and co-workers [116], since it has been shown that color management based on spectral properties of materials is the only way to ensure accurate color reproduction and address essential issues such as metamerism [61,[117][118][119][120]. Knowledge of the spectral reflectance properties associated with each pixel in a digital image of a painting has also opened up innovative applications, allowing, for example, the virtual restoration of original colors or simulations of varnish removal -techniques especially useful to the conservator [61,62,69].…”

Detection of image quality metamers based on the metric for unified image quality

“…In our another research, the metamerism, whereby two stimuli can match in color while having different spectral reflectance, was applied to detect areas that have possibility of repaint in historical materials in past times. [3], [4] The spectral reflectance of authentic icons painted on wooden plates was measured, and it was used to calculate a metric showing the degree of the metamerism.…”