Patent GB-549544-A (GB)
Title: Improvements in composite colour photography
IPC: G03B33/00
Filed: 1940-12-05
Abstract: 549,544. Composite colour photographs. TECHNICOLOR MOTION PICTURE CORPORATION. Dec. 5, 1940, No. 17303. Convention date, May 1. [Class 98 (ii)] Composite colour photographs are produced by illuminating a foreground and a light or dark plain backing behind it respectively to intensities such that the backing reflects more strongly or more weakly than the lightest or the darkest point of the foreground, making a multicolour record on multilayer sensitive material of the the foreground against the backing, and a similar record of the background, preparing also a silhouette mask of the foreground against the backing, and using said mask with one of the components when exposing to compose the photograph. A complementary mask for use with the other component may be made by printing from the first mask. In the method illustrated in Fig. 1, a background B<SP>1</SP> is photographed in a camera A on a multilayer sensitive film which is developed by reversal colour development or by the silver bleach-out dye process to a multicolour positive record PB. A foreground F and white backing FB, illuminated in the above-stated manner, are photographed in a camera B on a multilayer sensitive film which is similarly developed to a multicolour positive record PF. From the record PF a silhouette foreground mask FM is printed on high-contrast material, e.g. as described in Specification 547,216, and from FM is printed a complementary background mask BM. If composite colour separation negatives are desired for printing or for the production of inbibition matrices, the records PB, PF, each with its appropriate mask BM, FM, are printed in succession on three separate films, viz Nb using blue printing light, Ng using green light, and Nr using red light, which yield on development the desired negatives CNb, CNg, CNr. Alternatively, a single multicolour composite positive may be made by printing PB and PF, each with its appropriate mask, on to a multilayer sensitive film, employing for each a single exposure for all its colour aspects, or a separate exposure with coloured light for each aspect. Fig. 1 also illustrates a modified method of producing the silhouette masks, wherein the backing FB of the foreground F is black; in this case, the background mask BM<SP>1</SP> is obtained by printing the multicolour record PF<SP>1</SP> on high-contrast material, and the foreground mask FM<SP>1</SP> is printed from BM<SP>1</SP>. In another alternative, instead of making the mask FM (or BM<SP>1</SP>) by printing from the multicolour record PF (or PF<SP>1</SP>), it is made simultaneously with the said record in a splitbeam camera. In a modified process in which only one silhouette mask is used, the foreground F, in front of a black backing FB is photographed in a split-beam camera, the latent multicolour foreground record being made on a multilayer sensitive film in one beam, and the background silhouette mask BM<SP>1</SP> on a high contrast film in the other beam. The mask only is developed, and is then fed, together with the multilayer film bearing the latent multicolour foreground record, through a camera in which it is exposed to the background field, so that a composite multicolour positive is obtained on developing the film. From this, further copies on multilayer sensitive films, or colour separation records may be made as described above. The same camera may be used for both exposure operations, only one beam thereof being used for the second.