Maintaining the quality of aerial photographic products with time requires a simultaneous retention of both image and dimensional characteristics. These factors are prerequisites for maintaining aesthetic value and ensuring no distortion of information occurs. It is, however, the recent experience of archivists that many negatives and prints are suffering irreversible deterioration. Degradation is typified by image fading, the presence of surface crystalline deposits which obscure any image and signifcant dimensional distortion. This paper relates those factors which influence stability, principally temperature, relative humidity and oxygen, and correlates them to structural changes in the materials. In addition an overview is given of methods of monitoring and of inhibiting breakdown.