One of the most important attributes of color images is stability to exposure of light. Images that will be displayed indoors are usually subjected to accelerated testing by exposing them to simulated “daylight” that consists of radiation from a xenon lamp filtered through a soda-lime glass filter. Those images to be displayed outdoors are tested with a similar xenon lamp without the glass filter giving a higher exposure to ultraviolet light. The rate of photofade can depend on the type of polymer or dye, the availability of oxygen and humidity as well as the more obvious parameters of light intensity and temperature of the environment. We have attempted to investigate the rate of photofade of a yellow, magenta, and cyan dye in polycarbonate, polystyrene, polymethylmethacrylate, and a phenoxy resin to determine the impact of polymer type.Our results include the photolysis of dyes in solution, as well as in coated films. The dyes exhibited no fluorescence in an ethanolic solution at 77° K. Phosphorescence observed in the polymers was attributed to impurities. Decay times indicate a very high probability of energy transfer from the polymer to cyan dye. Results on photofade show that polystyrene and phenoxy resin are significantly worse than polycarbonate and polymethylmethacrylate. Common addenda used to improve dye fade in polymers had very little positive effect. 2-aminophenol improves photofade for the cyan and magenta dye while zinc di-n-butyldithiocarbamate slightly improves cyan photofade.
William H. Simpson, Jacob J. Hastreiter, Norman S. Allen, Sarita Sehti, "Photofade In Polymer Films: Rate of Fade in Films and Solution" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 767 - 770, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00087_2