Color Fastness of Sappanwood-Dyed Silk and Insights into the Clothing Life of the Heian Period

Abstract

The juni-hitoe is a traditional Japanese costume from the 10th century made of at least twelve layered silk kimonos. Sappanwood dye was often used to color the silk fabric, although it was subject to fading. In this study, silk was dyed with sappanwood and treated with various mordants. The dyed fabrics were examined for color fastness. Color fading due to ultraviolet rays was particularly high for the aluminum-based mordant, and the color of the silk was projected to fade within about four to six months of sunlight exposure. Alkaline perspiration had a relatively large effect on color fading ; in particular, a reddish color was transferred to a superimposed white fabric. However, when using an iron ion mordant, the degree of decoloration was relatively small. <br>These investigations show that silk fabric dyed with sappanwood easily fades in color due to various environmental factors, and color transfer to superimposed fabric is frequently seen. These findings afford insight into the color life of such fabrics during Japan’s Heian period. Thus, the costumes at the time presumably required periodic redyeing.