The natural and artificial degradations of cellulose triacetate based cinematographic film have been studied by moisture regain, viscometry, u.v. absorption, pH and degree of insolubilization. The effect of humidity, emulsion, plasticizer, negative and positive images and film can storage are investigated as well as the effect of plasticizer loss. A cross-sectional analysis on the films has also been carried out through both the reel diameter and width. The effect of humidity indicates that a minimum concentration of acetic acid is required in order to effect hydrolytic degradation of the film while negative and positive films show some significant differences in their physical and chemical ageing characteristics; in general positive films are less stable. A cross-sectional analysis on the films indicates that older films are more severely degraded due to a higher moisture content. Under both natural and artificial ageing, degradation is greater where the film is in contact with the environment; the emulsion layer and plasticizer offer some protection to the acetate base. This is associated with their ability to neutralize the acetic acid. Conventional iron can storage conditions have a severe catalytic effect on the degradation rate of the film. Plasticizer loss is accelerated under humid-acid conditions with increasing temperature but impaired by the emulsion layer acting as a diffusion barrier.