Cellulose acetate film
From The Art and Popular Culture Encyclopedia
Cellulose acetate film, or safety film, is used in photography as a base material for photographic emulsions. It was introduced in the early 20th Century by film manufacturers as a safe film base replacement for unstable and highly flammable nitrate film.
Beginning with cellulose diacetate in 1909, this innovation continued with cellulose acetate propionate and cellulose acetate butyrate in the 1930s, and finally in the late 1940s, cellulose triacetate was introduced, alongside polyester bases. These less flammable substitutes for nitrate film were called safety film.
The motion picture industry continued to use cellulose nitrate supports until the introduction of cellulose triacetate in 1948, which met the rigorous safety and performance standards set by the cinematographic industry. The chemical instability of this material, unrecognized at the time of its introduction, has since become a major threat for film collections.