ABSTRACT
Specific filters are recommended for some situations, such as when using certain combinations of color films and light sources, but to take full advantage of the benefits that filters offer, it is necessary to have a basic understanding of how filters function. The color terms most useful in discussing filters and color photography are red, green, blue, yellow, cyan, and magenta. All infrared filters for black-and-white photography have high transmittance of infrared radiation, but they vary in the width of the band of wavelengths transmitted. The filter factors for the light source can be determined by finding the antilogs of the horizontal displacement of each curve from the white-light curve at a specified density. The exposure adjustments required when filters are used with daylight-type and tungsten-type film are provided on the data sheets that accompany the film, usually in the form of an adjusted film speed rather than as a filter factor.
