- Film Decay and How to Slow It
Color Dye Fading
Since the introduction of modern color motion picture films in the 1950s (the older Technicolor process is a different story), color fading has become a growing concern. Color fading is caused by spontaneous chemical changes in the image dyes of color films. Many older films have taken on a distinct purplish cast, caused by the rapid fading of the cyan and yellow image dyes. Negatives, interpositives and prints are all affected in the same way. While earlier generations of color films would fade in just a few years when kept at room temperature, today's films are more stable; significant fading will occur in about 40 years at room conditions. Despite manufacturers’ efforts to improve the stability of their products, the only way to guarantee centuries of useful life for color films is to keep them in cold storage. The colder the conditions, the slower the fading, and the longer the lifetime of the film.
James M. Reilly. Storage Guide for Color Photographic Materials: Caring for Color Slides, Prints, Negatives, and Movie Films. Albany, NY: University of the State of New York, New York State Education Department, New York State Library, New York State Program for the Conservation and Preservation of Library Research Materials, 1998.