Photographic film is a sheet of plastic coated with an emulsion containing a light-sensitive chemical such as silver nitrate. Other modern light-sensitive layers consist of silver halide salts with variable crystal size that determine the sensitivity of the film. When the emulsion is subjected to controlled exposure to light (or other forms of electromagnetic radiation such as X-rays), it forms a latent image. Chemical processes can then be applied to the film to create a visible image, or photograph, that is stable when exposed to further light for viewing.
Black-and-white photographic film uses one layer of silver, whereas colour film uses a three-layer dye-based structure.
Because photographic film was ubiquitous in the production of motion pictures, or movies, these are also known as films.
The first roll film, allowing several images without opening the camera, was introduced by Kodak in 1895. See also film formats.
Companies that manufacture photographic film:
See also: Timeline of photography technology