Nitrocellulose (also: cellulose nitrate, flash paper, flash cotton, guncotton, flash string) is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it was originally known as guncotton. If the cellulose is not fully nitrated then it has found uses as a plastic film and in inks and wood coatings. Nitrocellulose plasticized by camphor was used by Kodak, and other suppliers, from the late 1880s as a film base in photography, X-ray films and motion picture films; and was known as nitrate film. After numerous fires caused by unstable nitrate films, safety film started to be used from the 1930s in the case of X-ray stock and from 1948 for motion picture film.