Abstract

A method for color correction is considered using two masks drawn from the subject and used for correcting the color separation negatives. The formulas for computing the exposure times and the gradations are in agreement with practical results, as far as letter press, offset, and gravure printing are concerned.

The exposure times of the masks and the red separation have to be carefully watched. The method allows accurate reproduction of the eight main colors, white, yellow, magenta, cyan, violet, green, orange, and black, and of a medium gray. The colors lying between them are reproduced with an approximation that is sufficient for many practical applications.

The rule that the three color separations have to be developed to the same gamma does not always allow a correct reproduction of gray. The reproduction of grays can be considerably improved by making use of nonlinear characteristic curves. This is valid for letter press, offset, and gravure printing as well as for reproduction methods based on subtractive mixture.

© 1952 Optical Society of America

Color Correction with a Single Gray Mask in a Halftone Color Print

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Theory of Subtractive Color PhotographyIII. Four-Color Processes and the Black Printer*

J. A. C. Yule
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Color Film Analysis from Integral Density Data*

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Subtractive Color Photography: Spectral Sensitivities and Masks*

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