High Quality Content by WIKIPEDIA articles! 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.