An Introduction to the Technology of Color Films (Film Colorimetry) — A Tutorial Paper

An analogy between the color photographic system and color television reproduction of an original scene is outlined. There are four basic steps or stages common to both technologies, color film and color television: (1) color separation, (2) input processing, (3) color synthesis, and (4) display. This paper, a tutorial discussion for manufacturers of telecine equipment, sets forth the basics of film colorimetry. The structure of color films is explained, as well as the basics of subtractive color reproduction theory. The fundamentals of sensitometry are touched on, and the aims of tone and color reproduction are defined. The rest of the paper is dedicated to the discussion of the color photographic dyes and their properties. The formation of the dyes by means of couplers incorporated in the photographic emulsion layers is explained, and the spectrophotometric properties of these dyes are elucidated. An important imperfection of these dyes consists in their having so-called unwanted absorption bands which make faithful rendering of the original scene difficult. However, the deleterious effect of the unwanted absorptions can be greatly reduced by the use of masking, a technique which practically nullifies the influence of the unwanted absorptions of the dyes. Two types of possible masking techniques are described: masking by means of colored couplers and masking by means of the interlayer interimage effect. Both can be combined. Presently manufactured motion-picture filmstocks incorporate one or both of these technologies. With these techniques, an acceptable reproduction of the original scene, pleasant to the eye, can be obtained.

Print ISSN

0036-1682

Published

1979-11

Content type

Original Research

DOI

10.5594/J10358