Indeed, thermal effects occur incessantlyin light or darkness. The chart below illustrates the importance of thermal effects being factored into image stability tests along with light effects. Only 100 yrs. This shift is what causes some manufacturers, prints to take on a reddish cast over time. Primarily because of thermal effects, prints will fade even in darkness as will clothing, printed documents and other dye-embedded items.
All dyes fade.
For photographic prints kept entirely in the dark, in an album or storage box, for example, identifying the kinetics of dye fading and print staining is essential to calculating the rate of each. Some leading photographic paper manufacturers, therefore, use it as the basis for their image stability data. It is currently the only accepted method for calculating dark stability. In fact, in 1990, ANSI incorporated it into Standard IT9.9 Stability of Color Photographic Images-Methods for Measuring. In contrast, simple single-temperature accelerated tests can produce misleading results, since they omit data on the temperature sensitivity of the fading or staining process.