Digital imaging technologies have progressed significantly over recent years to the point where modern hard copy output from dye diffusion and more recently ink-jet printers can be compared, in terms of image quality at least, with silver halide. Despite these advances in the print quality, image preservation remains a key technical challenge. In particular the preservation of images during exposure to light continues to attract much interest.The light stability performance of a series of hydroxyl functional azo dyes, in which the functional groups were electronically isolated from the chromophore, has been studied in a range of polymeric hosts. In these systems three distinct interactive dye species have been identified by infra-red spectroscopy; dye-dye, dye-polymer and intramolecularly bonded dye molecules. The relative proportion of each has been shown to be dependent on the concentration of dye, the number of functional groups on the dye molecule and the ability of the host polymer to take part in hydrogen bonding with the hydroxyl groups. The amount of fading exhibited by these systems has been correlated with the concentration of dye, the dye-polymer interaction strength and the number of functional groups present on the dye. Thus, it has been shown that the amount of fading is strongly dependent on the proportion of dye-dye to dye-polymer species with higher levels of dye-dye interaction promoting fading.
A. A. Clifton, N. Nugent, "Lightfastness Performance In Digital Imaging: The Role Of Dye-Dye And Dye-Polymer Interactions" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP16), 2000, pp 762 - 766, https://doi.org/10.2352/ISSN.2169-4451.2000.16.1.art00086_2