GB405356A - Improved method or process for the production of sound records on color or monochrome films - Google Patents

Abstract

405,356. Combined sound-record and colour-picture films. MURRAY, H. D., SPENCER, D. A., 118, Fulham Road, South Kensington, London, and THORNTON, J. E., 8, Hill Street, Jersey, Channel Islands. Aug. 18, 1932, No. 23135. [Class 40 (ii).] Relates to the production of sound records on multi-colour or monochrome films, of the kind in which pictures in relief are produced in a soluble coloured colloid superposed on a layer of hardened colloid, by forming a silver image in the latter layer, differentially hardening the soluble coloured colloid adjacent to the silver image, and washing out the unhardened coloured colloid. According to the invention, a sound record printed on the film is converted into a colloid relief image by the same process as that used in producing the colour pictures. Thus, in carrying out the process, the sound track is not protected from the action of the bleaching solution. The colouring matter in the sound track may be different from that in the picture areas. A process is described, in which the sound track is coated by means of a roller, weir, &c., with gelatine or other colloid coloured black by a finely dispersed pigment such as lamp black, or by an insoluble dyestuff, &c. The remainder of the film is coated with a blue-green or orange pigmented colloid, which need not be carefully confined to the picture area, but may in places overlap the black colloid without detriment, since all unwanted colloid is dissolved away by warm water treatment after the bleaching of the silver images and consequent formation of the relief images. In another process, especially suitable for producing variable area sound records, the sound track is overlaid with the same coloured colloid as is used for one series of pictures, e.g. orange red, and in order to increase the efficiency for soundreproduction, a substance such as an insoluble quinine product or aesculin may be added to the colloid, to filter off ultra-violet rays. Instead of pigmenting the colloid covering the sound track, this colloid may contain colourless substances such as lenco-bases of dyestuffs, which become dark or black on suitable aftertreatment. Alternatively, there may be used on the sound track a coloured compound which does not obstruct actinic light until it has been suitably treated ; e.g. a blue dye lake, whose colour is changed by acid or alkali to red, may be used. In a further example, the colloid covering the sound track may contain a stable green colouring matter, in addition to a blue dye lake which, after exposure and appropriate chemical treatment becomes orange, the resultant layer being black. The invention may be used in various ways with the materials and processes described in Specifications 371,077 and 377,706, [both in Group XX].