Nitrate film: composition and construction
Cellulose nitrate film base was made from cotton linters -- the material that remained after the majority of usable cotton was removed from the seeds (National Film and Sound Archive, n.d., and Goetz & Sons, n.d.) -- which was mixed with nitric and sulphuric acids. The resulting polymer was mixed with camphor. It was then cast into a thin layer of film which was very flexible. The flexibility of this base material allowed film to be advanced in the camera and led to more non-professionals taking photographs. It also led to the advent of moving images (National Film and Sound Archive, n.d.).
Due to its high level of nitrate, the film stock is very combustible. The camphor, which acts as the plasticiser, adds to the flammability of the film. (National Film and Sound Archive, n.d.).
Nitrate film was produced in many formats and sizes. In addition to being used for 35mm moving image film, nitrate was used in 17, 17.5, 21, and even 75mm sizes. Besides being used to capture moving images, it was also used for still photographs and X-rays. (National Film and Sound Archive, n.d.).