Wavelength Dependence on Light Deterioration of Oriental Lacquer Film

Abstract

The light deterioration of oriental lacquer film is suppressed when a special fluorescent lamp for museums is used instead of a conventional lamp. However, the light deterioration was anticipated to occur from the past study even if such special lamps were used, when the intensity of luminance was increased. In this study, the wavelength dependence of light deterioration on the film was examined using several fluorescent lamps radiating light of different wavelengths. The gloss of the film decreased a little in the radiation of the visible rays, though the wavelength dependence was not confirmed. The effect on the color difference was not clear. On the other hand, the surface oxidation advanced by the radiation of visible ray, though the oxidation was not so much as compared with that of ultraviolet rays. The content of double bonding on the film surface also decreased by irradiating the visible light having short wavelengths. Therefore, it is sure that the chemical change steadily progresses due to the visible rays, though the apparent change is small in an exposure test for one year. Thus, we conclude that the effect due to visible light was considerably smaller than that due to the ultraviolet ray.