Study On The Irradiation Damage Of Common Light-sensitive Cultural Relic Materials

In museum exhibition lighting,illumination will cause irreversible damage to cultural relics,and lighting conditions need to be strictly controlled.At present,the index of exhibition lighting for light-sensitive cultural relics is only 50 lx.Light-sensitive cultural relics are often rich in color and need to be observed effectively in high illumination environment.How to improve lighting conditions without increasing damage to cultural relics is a main problem to be solved.In order to improve the level of exhibition lighting,reducing the damage of cultural relics is the primary prerequisite.If the light source with the least damage to the cultural relics is used for illumination,and the cultural relics are stored in nitrogen atmosphere,the aging of the cultural relics can be reduced availably.Through the above two ways to reduce the irradiation damage of cultural relics,compared with the existing lighting conditions,what extent can the lighting level be improved to,still lack of effective evidence support and systematic analysis.This paper studies the fading and aging rules of common light-sensitive cultural relic materials under different atmospheric environments,selects suitable experimental objects,designs an aging experimental system and conducts experiments,and quantifies and analyzes the experimental results by color difference analysis.The work contents of this paper include:(1)According to the main material composition of light sensitive cultural relics,two groups of color samples of different substrate were designed and made by traditional technology,that is,traditional Chinese painting pigments samples on rice paper(cinnabar,ochre,azurite,malachite,graphite,cyanine,carmine,phthalocyanine blue,eosin),and plant dyestuff samples on silk(amur corktree,madder,gardenia,sophora japonica,lithospermum,sappan and indigo).(2)The experiment system of continuous light irradiation aging is designed for different atmosphere environment.In view of the large infrared light content of halogen tungsten lamps,the continuous heating aging experiment in atmospheric environment is designed to analyze the damage mechanism of Infrared light on cultural relics.The experimental results and analysis conclusions of the above study are as follows:(1)The results of continuous light irradiation aging in atmospheric environment show that: 1.The visible light source with the least blue light content has the least damage to the cultural relics.(After total exposure equivalent to 50 lx exposure for 18 years,50 000 lx/year for 140 years,).2.Silk dyes are more sensitive to light than traditional Chinese painting pigments.3.LED with low correlated color temperature will cause least damage to cultural relics.4.Color temperature cannot distinguish the phenomenon of different spectra with the same color temperature.This paper propose to use proportion of blue light as the limited index for LED,which can more effectively reduce the damage to cultural relics.(2)By comparing the experimental results of irradiating and heating aging,it is found that under the light irradiation environment,the leading impact of Infrared light is that increase of surface temperature of cultural relics catalyzes the photochemical reaction of materials.(3)The results of the continuous lighting irradiation aging in the nitrogen environment show that: The damage of the cultural relics caused by the light irradiation could be effectively reduced in the nitrogen environment.Storage of cultural relics in nitrogen environment can effectively improve the level of exhibition lighting.The above research work shows that: In the process of museum exhibition lighting,the use of LED light source with lower blue light content and nitrogen to store cultural relics can improve the lighting condition without increasing the damage caused by light irradiation on cultural relics.This study can provide important guidance for the revision of the lighting condition of museum exhibition in the future,and play a positive role in promoting the development of exhibition lighting in China and even in the world.