General term for any thin (less than 0.010 inch), flexible, unsupported material used as a printing substrate. A substrate with a thickness of more than 0.010 inch is called a sheet or sheeting.
In photography and other types of imaging, a material—commonly comprising a photosensitive emulsion on an acetate base—which receives images either photographically by exposure to actinic light or by lasers driven by digital data. Film often needs to be chemically processed to develop the latent images. In phototypesetting, photosensitive paper is also called film.