Patent GB-538628-A (GB)
Title: Improvements in composite color photography
IPC: G03C7/00
Filed: 1940-02-13
Abstract: 538,628. Composite colour photographs. TECHNICOLOR MOTION PICTURE CORPORATION. Feb. 13, 1940, No. 2750. Convention date, July 18, 1939. [Class 98 (ii)] In the production of a kinematograph film combining colour aspects of a background, and of a foreground taken separately against a uniform backing, the background and foreground are illuminated with light containing the ranges of said colour aspects ; the uniform backing is prepared and illuminated so that it sends out light lacking one or two of the colour aspect ranges ; from the colour records of the foreground two are selected which record and do not record, respectively, a range lacking in the light sent out by the backing ; and, during the process of combining the corresponding aspect records by printing them on the film, said mask is employed to protect the area of one record while the other record is being printed. A second mask may be printed from the first mask, and the final colour photograph composed by printing the background records through one of the masks and the foreground records through the other mask. One method of procedure is illustrated in Fig. 3. Bb, Bg, and Br are colour record negatives made from the background illuminated with white light. Fb, Fg, and Fr are colour record negatives of the foreground illuminated with white light, against a yellow backing illuminated with green and red light. This light should be such that green reflected from the backing is of greater intensity than the green reflected from any point of the foreground. Both sets of records may be made in a colour separation camera. From the negative Fb is printed a positive Pb, and the first mask BM, for printing the background negatives, is made by exposing a lightsensitive film consecutively under the positive Pb and the negative Fg, the film used being capable of yielding high contrast between backing and foreground areas, e.g. one having an emulsion made as described in Specification 263,650, [Class 98 (ii)], care being taken to avoid preexposure or fogging, the effect of which is described in Specification 263,331, [Class 98 (ii)]. From the first mask BM is printed the second mask FM, for printing the foreground negatives. Three films Mb, Mg, Mr, of the kind suitable for preparing imbibition printing matrices, are printed respectively, first under the background negatives Bb, Bg, Br through the mask BM, and then in register under the foreground negatives Fb, Fg, Fr through the mask FM. The films are developed to gelatine reliefs by a wash-off process which removes the unexposed gelatine, and the final positive P is printed by imbibition therefrom. The red record may be used instead of the green record in preparing the masks. In an alternative method, the foreground mask FM is made by printing a positive from the negative Fg, and making a print from this positive superimposed on the negative Fb. The background mask BM is copied from this. In further alternatives, (1) the backing is painted minus red and illuminated with minus red light, and the red record is used with either the blue or the green record in preparing the masks ; (2) the backing is painted white or blue and illuminated with blue light, and the blue record is used with either the green or the red record in preparing the masks. The printing apparatus described in Specification 546,667 may be used.