Light-fading tests were conducted for the several consumer and commercial photographic prints which were available in the current market. The print life of those photographic prints was evaluated subjectively using some sets of endpoint criteria, and also assessed visually by observers. It was confirmed that the evaluation based on the colour difference produced results that correlated well with those of the visual assessment.
Hiroshi Ishizuka, Evert Groen, Nobuhiko Uchino, Yoshi Shibahara, Shin Soejima, Wil der Kinderen, "Endpoint criteria for evaluation of image permanence of photographic prints" in Proc. IS&T Printing for Fabrication: Int'l Conf. on Digital Printing Technologies (NIP35), 2019, pp 197 - 202, https://doi.org/10.2352/ISSN.2169-4451.2019.35.197