Abstract
The effect of NO2, one of the most important environmental factors in the conservation of cultural properties, was investigated with respect to the fading of dyed fabrics. Ambient NO2 concentrations at 19 sites in museums and galleries were measured by a passive sampler on a monthly average basis for one year. It was found that the annual average concentration ranged between 20-60 ppb at the outdoors, 7-20 ppb in the exhibition rooms and 2-7 ppb in the showcases. Airconditioning, especially with a charcoal filter, was found to be effective in controlling ambient NO2 concentration. Aclosed environmental system such as a Japanese traditional warehouse is also good for minimizing low NO2 concentration. Fading-test pieces dyed by brazilin, Chinese tannin, purpurin and myricetin, all selected from Japanese traditional dyestuffs, were exposed to the museum and gallery environment for one year. As a result of dese-response characterization, The correlations between NO2 dose and color difference were found to be fairly good for all of the dyestuffs tested here. Moreover, a substrate effect was clearly observed that the cotton piece was faded more than the silk one. It is considered that it occurred due to the oxidation of the dyestuff by NO2. In addition, hydrolysis might occur due to the acidity of NO2in the case of Chinese tannin.
