Patent GB-556631-A (GB)
Title: Improvements in or relating to picture and sound cinematography
IPC: G03D15/00
Filed: 1942-06-15
Abstract: 556,631. Kinematograph picture and sound films ; colour photography. BROOKES, N. E. (Technicolor Motion Picture Corporation). June 15, 1942, No. 8153. Drawings to Specification. [Class 98 (ii)] In processing films bearing a picture zone and a sound-track zone, one zone is coated with lacquer insoluble in the following processing baths, the other zone is processed, the lacquer is removed with a solvent, this solvent is removed with another solvent miscible with the lacquer solvent and with the first subsequent processing liquid, and the first zone is then processed. The invention is illustrated as applied to the processing of a film comprising a transparent support coated in turn with red, green, and blue-sensitive layers. After printing the component picture records either successively or simultaneously from a multicolour original, and also the sound record, the sound-track zone is covered with fast-drying opaque varnish impervious to the aforesaid processing liquid ; the picture zone is hardened; the picture components are simultaneously developed to silver; the picture zone only of the red-sensitive layer is flashed with red light through the support, and the cyan component is colour developed therein ; the picture zone only of the blue-sensitive layer is flashed with blue light from the emulsion side, and the yellow component is colour developed therein. For these steps, colour developers are used too weak to carry development to completion, and thereafter development of the red and blue sensitive layers is completed with a black and white developer before completing the picture by colour developing the magenta component in the green-sensitive layer; this may be done after exposing the layer to light, or by using a chemical fogging agent in the magenta developer. Silver in the picture zone is removed by bleaching it to a silver salt soluble in hypo, and fixing out this salt together with any residual silver halide ; the protective covering is removed by a varnish solvent, and the film is washed to remove the solvent, first with a liquid such as isopropyl alcohol which is miscible both with water and with the solvent, and then with water only ; and the sound record is finally developed with an ordinary black and white developer, followed by fixing, washing and drying. An apparatus for performing all these operations seriatim is described, comprising a pair of projectors for printing the picture and sound records ; a device for coating varnish on the sound track zone only, comprising a bath of varnish which is applied by a coating roller dipping into the bath ; a series of conventional processing tanks ; optical devices for flashing the red and blue-sensitive layers at the appropriate stages ; and a final drying chamber. In the tank in which the varnish covering is removed the film passes zig-zag over upper and lower sets of rollers, and midway the bights pass between idle rollers and rotary brushes 5 as of felt, beltdriven from a motor so that their contacting surfaces move in a direction opposite to that of film travel. The device for flashing the redsensitive layer may comprise a tank with a transparent base through which the red light is projected on to the film, and containing water in which the film is immersed during the flashing. A varnish composition is given comprising carbon black, nitrocellulose (30-40 second), ester gum, dibutyl phthalate, butyl acetate, alcohol, amyl acetate, ethyl alcohol, and toluene ; and a solvent for removing it comprising the five lastmentioned ingredients. Specifications 500,796, 507,841 and 541,771 are referred to.