The Deterioration Characteristics of Archival Cellulose Triacetate Base Cinematograph Film

Abstract

Many cellulose triacetate base cinematograph films, originally introduced in the 1950s,- are now exhibiting signs of irreversible deterioration. This degradation is characterized by the release of acetic acid from the film base and plasticizer deposits on the film surface. Such degradative processes subsequently result in loss of image. Copying of film is both costly and results in loss of image resolution. We have therefore undertaken studies to establish the physical and chemical degradation characteristics of such films. Here the role of factors such as emulsion layer, plasticizer and film container have been considered along with the influence of external environmental factors such as temperature and relative humidity. The relationship between both naturally and artificially-aged filmstocks has been considered, since this is necessary not only for a reliable assessment of film performance but for a realistic interpretation of the mechanistic processes involved. An understanding of the latter is required if any reasonable attempt is to be made at prolongment of film life.