Factors influencing the fading of Cibachrome S(R)S materials in the dark and upon exposure to light are discussed. Very long testing periods are required to study the dark fading process at temperatures up to 77°C and 60% relative humidity (RH). After 112 days at 77°C/40% RH, hardly significant density changes could be observed. Above 80°C and 70% RH the absorption spectra of the Cibachrome azo dyes change noticeably within a week. This is mainly due to partial deaggregation of the azo dyes into monomers. This deaggregating process is reversible, as shown by experiments. Even at 91°C/90% RH, the irreversible chemical degradation is very slow. Comparative data regarding the light fading properties are also given. They prove the excellent stability of the azo dyes toward photo-oxidation.