Investigation of the degradation mechanism and discoloration of traditional Japanese pigments by multispectral imaging

Pigment degradation has been a subject of interest among researchers in the field of cultural heritage studies. Knowing how pigments behave when subjected to different elements such as high temperature, humidity, electromagnetic radiation and many more others is of prime importance. In this study, the effects of subjecting Japanese pigments to high temperature were investigated. Focus was given on the effects in terms of pigment discoloration and the micromechanism of degradation. Multispectral images were used to track the changes in color and spectral reflectance by reconstructing colorimetric and spectral information from the images. The multispectral images were taken using a high-resolution flat-bed scanner equipped with a line-CMOS camera. In addition, the pigments were characterized using commercially available spectrometers, X-ray diffraction, X-ray fluorescence spectroscopy and X-ray absorption fine structure were used to ascertain the influence of high temperature exposure of the pigments. The high resolution multispectral scans gave the most valuable insights into the discoloration and micromechanism of pigment degradation since they provide both analytical and visual information.