Patent GB-427472-A (GB)
Title: Improvements in colour photography
IPC: G03C7/22
Filed: 1933-09-21
Abstract: 427,472. Colour photography. KODAK, Ltd., Kingsway, London.-(Assignees of Mannes, L. D., and Godowsky, L. ; Kodak Park, Rochester, New York, U.S.A.) Sept. 21, 1933, No. 26084. Convention date, Sept. 21, 1932. [Classes 97 (i) and 98 (ii)] Relates to a process for the production of three-colour photographic records, particularly for motion pictures, comprising first, obtaining a record in two colours of three colour sensations by forming in one area of a first sensitive element having two superposed differentially sensitized layers a latent image of one colour component in each layer and in another area latent images of two other components in the respective layers, transforming the latent images in the two layers into images of two different colours, and then forming on a common area of a photographic element three registering differently coloured images corresponding respectively to the three colour sensation records ; and consists in producing a record in three colours by exposing an area of a second sensitive element carrying three layers to printing light of three different colours, transmitted respectively by the three colour sensation records of the first element, to which colours the three layers are differentially sensitive. The two component images in one area may be printed with a single, two-colour beam and the third component image in the other area with a beam of a third colour. Thus a negative film F, Fig. 3, comprising a support 1 carrying superposed layers 2, 3, of green and red sensitized emulsions, separated by a thin gelatine layer 4, is exposed in a two-colour split-beam camera in which the light is transmitted through a rhomb 11, Fig. 2, cemented to the partly-silvered face 5 of a prism 12 through yellow and blue filters 9, 10 so that, simultaneously, the green and red sensations are recorded differentially in one frame A and the blue sensation is recorded, in both layers, in an adjacent frame B. The latent images in the two layers are then processed to dye images in various colours, e.g. images 16, 18, in the green-sensitive layer 2, Fig. 3 are processed to minus green, and images 15, 17 in the red-sensitive layer 3 to minus red ; and the colour - processed negative is then printed, by projection, on to a three-layer material, comprising a support 20, Fig. 8, carrying on one side, two emulsion layers 21, 23 sensitized respectively to green and red, and on the other side, a single layer 24 sensitized to infra-red. The printer, Fig. 6, comprises a rotary shutter 32 furnished with open and reflecting sectors separated by opaque sectors. Light from a lamp 30 is transmitted through a filter 41, which cuts out extreme red and infra-red and blue, through the open sector and through the green and red record frame A of the negative film N to the positive film P ; light from a second lamp 31 is passed through an infra-red filter 42 and reflected by the shutter 32 through the blue record frame B of the negative film N which is advanced two frames for each frame of the positive film. The exposed positive film is then processed to the negative colours of the respective colour sensations, e.g. the image 43 Fig. 8, in the lower, green-sensitive layer 21 is processed to minus green, the upper image 44 in the red-sensitive layer 23 to minus red and the image 45 in the infra-red sensitive layer to minus blue. Colour processing of the negative and positive materials is effected by colour development with a colour former, as described in Specification 376,838, utilizing the methods of Specifications 427,616. 427,517, 427,518, 427,519 and 427,520. Details of the processing are given. The two sides of the positive material may be processed differentially by flotation methods. Duplicate negatives may be obtained by contact printing with yellow light upon similar material, either via a positive or directly by reversal. The sensitivity and order of the layers of the negative material may be other than red and green, and the gelatine separating- layer may contain a screening dye ; and the layers may be processed to other colours, e.g. blue or blue green and yellow or orangeyellow, the double coating of the positive material being sensitized to blue and orange. Printing may be effected with the printer shown in Specification 13430/15, [Class 98 (i)]. The invention may be applied to still pictures, on plates or films. Specifications 327,714, 333,902, [both in Class 2 (ii)], and 356,308, [Group IV], also are referred to.