GB1171161A - Photographic Color Image Formation using Colour Separation Negatives - Google Patents

Abstract

1,171,161. Corrected photographic colourseparation positives. J.B. PEATY. Nov. 14, 1966, No.50890/66. Heading G2C. Colour-corrected photographic colour separation positives for use in graphic colour reproduction are made by (a) forming colour separation negatives, (b) forming colour control negatives which are similar to the colour separation negatives but have been underexposed and overdeveloped to increase the contrast, (c) forming selective positive-negatives by using individual colour components of the light image of the original to be reproduced in register with colour control negatives, (d) forming positives using the separation negatives in register with the selective positive negatives and then (e) registering the positives obtained with their corresponding selective positive negatives. When the conventional red, green and blue colour components of a colour transparency are used to form cyan, magenta, yellow and black colour separation negatives and cyan, magenta and yellow control negatives, up to four selective positive negatives may be made as follows by exposing:- (i) The green component image of the transparency in register with the yellow colour control negative; (ii) the red component image in register with the magenta colour control negative; (iii) the blue component image in register with the cyan colour control negative; and (iv) the green component image in register with the cyan colour control negative. In preparing the positives, the black (or key) separation negative may be registered with selective positivenegatives (ii) or (i) and (ii) together; the cyan separation negative may be registered with selective positive-negative (ii); the magenta separation negative may be registered with selective positivenegatives (i) and (iv); and the yellow separation negative may be registered with the selective positive-negative (iii). The positives obtained are then placed in register with their corresponding selective positive-negatives to obtain the corrected positives, e.g. the yellow positive (that obtained from the yellow separation negative) with selective positive-negative (i); the magenta positive selective positive-negative (ii) and the cyan positive with selective positive-negative (iii).