〔報告〕 光明寺所蔵羅漢図に使用された彩色材料

In a previous study, an optical investigation of the arhat painting (rakan-zu) owned by Komyoji in Tokyo revealed that the painting had been repaired several times and suggested that the coloring materials used for the supplemental silk portions were different from those used for the original silk portions on the left wing of the Jivamjivaka (gumyo-cho) of the painting. In the present study, with the main objective of clarifying the differences between the coloring materials used for the supplemental and original silk portions, an analytical investigation was conducted at Komyoji by using visible and near-infrared reflectance spectroscopy withahyperspectral camera and X-ray fluorescence analysis (XRF). As a result, on the left wing of the Jivamjivaka, the coloring materials used in the original silk sections are assessed to have been painted with the blue pigment gunjo (made of azurite) and the green pigment rokusho (made of malachite), both of which have been used for a long time in Japan and China. On the other hand, the coloring materials used in the supplemental silk parts are possibly new coloring materials that became available during the modern period, judging from the color and chemical composition of the particles. In addition, the reddish-blue pigment used to paint the hair of Shakra Devanam Indra (Taishakuten), which is not present on the supplemental silk parts, suggests that it is a new coloring material introduced in the modern period. Other coloring materials used in the painting are confirmed to be cinnabar/vermilion, lead red, and lead white, all of which have been used in Japan and China since the ancient times.