The artificial and natural degradation of cellulose triacetate base motion picture film material has been studied using viscometry, moisture regain, acidity, infrared spectroscopy, and hydroperoxide analysis. Under both natural, i.e., archival, and accelerated aging conditions, there is a direct correlation between the moisture regain of the film material, acidity, and decrease in viscosity. From these results, two degradation processes are identified. The first is an acid-catalyzed hydrolytic deacetylation of the ester functionality, while the second is an acid-catalyzed hydrolytic oxidative scission of the main cellulose chain. Oxidative degradation and deacetylation of the polymer is more significant in an open than a closed environment. Iron is shown to be absorbed into the film during storage from the metal container and is acting as a powerful catalyst in accelerating the degradation and deacetylation processes. This is confirmed by doping the film with iron. The initiation process is shown to be associated with the iron-catalyzed decomposition of hydroperoxide groups. Studies on the physical characteristics of the film material indicate that the gelatin emulsion layer imparts some degree of stability to the film base due to its ability to scavenge and neutralize the acetic acid and partially prevent the diffusion of oxygen into the film. The plasticizer also imparts stability due to its ability to coordinate with the iron.