TITLE:
Degradation of Japanese Lacquer under Wavelength Sensitivity of Light Radiation
AUTHORS:
Kosuke Nakagoshi, Kunio Yoshizumi
KEYWORDS:
Japanese Lacquer, Degradation, Wavelength Sensitivity, Monochromatic Light, Spectral Reflectance, Visible Light
JOURNAL NAME:
Materials Sciences and Applications,
Vol.2 No.10,
October
18,
2011
ABSTRACT: Degradation of Japanese lacquer caused by light irradiation was examined at various wavelengths. By exposing lacquer specimens to a narrow monochromatic light band isolated from dispersed polychromatic light emitted by a Xe lamp source, the wavelength sensitivity characteristics of lacquer degradation could be determined on the basis of radiant energy. Tame-Urushi (brown) lacquer displayed peak degradation maxima at 220 and 315 nm. A broad shoulder peak was also observed in UVA. For Shu-Urushi (cinnabar) lacquer, in addition to peaks in the UVA–UVB range, a large degree of degradation was observed following exposure to light in the visible range. Ao-Urushi (green) lacquer showed similar characteristics, although it was less prone to degradation. Similarly, Shin-Urushi (black) lacquer showed little change in response to light, although UV light caused limited degradation. These results indicate that along with the damage caused by UVA and UVB, visible light in the range 510 - 650 nm may also have a significant degradation effect. Our results provide experimental evidence that Japanese lacquer responds differently to light of various wavelengths and that specific wavelengths, including visible light, can cause significant degradation.