Film which complies with standard requirements relating to difficulty of ignition and slowness of burning. 1Nitrate film does not meet these standards.
In the United Kingdom the requirements are specified in BS 850. A photographic film whose base is fire resistant or slow burning as defined by ANSI document PH.1.25, PH22.21, and by various fire codes.
At the present time, the terms ‘safety base film’, ‘acetate base film’ and ‘polyester base film’ are synonymous with ‘safety film’.
References
1British Standard Glossary of Terms used in the Motion Picture Industry