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Eastman Color

Description

“The Eastman Colour Films are multilayer films of the type in which the layers are not separated after exposure. Films of this class are known as Multilayer, Monopack or Integral Tripack. “Multilayer” is descriptive not only of this particular group of films, but also those in which the layers may be separated after exposure, while “Monopack” is liable to be associated with a particular process which has been quite widely employed by Technicolor. “Integral Tripack” is therefore adopted as the most convenient term for describing the Eastman Colour Films.

Three types of Eastman Colour Film are manufactured. These are the Colour Negative Film, intended for use as the picture negative material in the camera; the Colour lnternegative Film, used for a similar purpose to black-and-white duplicating negative film; and Colour Print Film, which may be employed in preparing prints from either the Colour Negative or Colour lnternegative. A special black-and-white Separation Positive Film is also provided and this is intended for use in preparing three separation positives from the Colour Negative. The separation positives form an intermediate link with the Colour Negative when making a Colour Internegative, so that their function is similar to that of a master positive in a black-and-white system.

Integral tripack camera films have the advantage that they may be used in a standard black-and-white camera, and apart from a check on the colour correction and focus of the lens, no special precautions are necessary. It is of interest to note that the colours of integral tripack negatives, as well as the densities, are reversed compared with the original scene.

The coloured images in Eastman Colour Films are produced by a method known as dye-coupling development. For this a special developing agent is used in conjunction with a second compound known as the colourforming coupler. Photographic development is a process of chemical reduction brought about by the developing agent, which is oxidized in proportion to the amount of silver formed. The oxidized developing agent combines with the colour forming coupler to create a dye of appropriate colour, the concentration of which is proportional to the amount of silver in the image. The dye thus formed must be insoluble in water so that the reaction shall be quite local and a dye image of high resolution obtained. The silver image is removed at a later stage of the process.

Three colour-forming couplers provide the appropriate dyes and are incorporated in the relevant emulsion layers.”

(Craig, G.J. (1953): Eastman Colour Films for Professional Motion Picture Work. In: British Kinematography, 22,5, 1953, pp. 146-158.)








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