The yellowing of thymol in the display of prints

Abstract

Framed and glazed prints have been found to yellow rapidly when on exhibition. It was found that the frames all contained the fungicide thymol. Experimental work has shown that the discoloration is caused by photoxidation. The discoloration was present in the paper and in the polymethyl methacrylate glazing. Mass spectroscopy has revealed the presence of a polymer of thymol; there was no evidence for the expected oxidation products. © 1986 Maney publishing.