Digital Color Management: Encoding Solutions, 2nd Edition

C

Photographic Media

Three principal types of conventional photographic media are referred to throughout this book: photographic negative films, such as those widely used in still and motion picture cameras; photographic print media, such as photographic papers and print films respectively used for making reflection and transmission prints from photographic negative films; and photographic transparency films, such as projection slide films and larger-format sheet films generally used with back illumination.

Photographic negative films and print media

Figure C.1 shows a simplified cross-section of a photographic negative film. The film has a blue-light-sensitive layer, a green-light-sensitive layer, and a red-light-sensitive layer coated on a transparent support. Because the green-light-sensitive and red-light-sensitive layers are also inherently sensitive to blue light, a yellow filter layer is coated above these layers to prevent blue light from reaching them. The yellow filter layer is made colorless during subsequent chemical processing of the film.

The light sensitivity of each layer is due to the silver halide grains that are dispersed within the layer. The grains of each layer are chemically treated during the manufacturing process in order to produce the appropriate spectral sensitivity for the particular layer. The resulting red, green, and blue spectral sensitivities for a typical photographic negative film are shown in Figure C.2. Also dispersed in each layer is an ...