Patent GB-516536-A (GB)
Title: Photographic films especially colour films bearing sound tracks
IPC: G03C7/24
Filed: 1938-06-27
Abstract: 516,536. Photographic sound and picture films. SCHINZEL, K., and SCHINZEL, L. June 27, 1938, No. 8950. Convention date, June 25, 1937. [Class 98 (ii)] In the production of a monochrome or multicolour picture image in one or more emulsion layers and a sound record in a separate emulsion layer, all the sensitive emulsion layers being carried on a single support before exposure of any of them, a silver chloride layer or layers is used for the picture image and a silver bromide layer for the sound record, or a silver bromide layer or layers for the picture image and a silver chloride layer for thesound record, producing the latent sound and picture images in the respective layers and separately developing such sound and picture images. The sound and picture records may be differentially processed by developing the image in the silver chloride layer without developing the image in the silver bromide layer. The image in the silver chloride layer' may be selectively developed with a sodium quinone sulphonate developer and the image in the silver bromide later developed with a hydroquinone, pyrocatechin, pyrogallol: or amidol developer. Either record may be recorded and developed before recording the other record. The material may comprise three differentially colour sensitized gelatino-silver bromide emulsion containing colour coupling components and a fourth silver chloride emulsion, all on a single support. Alternatively the material may comprise three silver chloride layers and one silver bromide layer, the latter being sensitized for infra-red or separated from the silver chloride layers by an ultra-violet absorbing filter. The sound record is printed after recording the picture images. The picture images are developed selectively with quinone sulphonic acid and sodium sulphite, and the sound image is developed and reversal coupling development effected in the three silver chloride layers by development with p-aminodimethylaniline. The reduced silver is removed, the residual silver bromide developed and the element fixed. In a modification, the residual silver bromide is developed to a dye image and then all reduced silver removed with Farmer's reducer. A fine-grain silver chloride emulsion to be used for recorded sound may be hypersensitized. The colour sensitizers in the silver bromide emulsions used for recording the picture images may be rendered non-diffusing by treatment with phosphotungstates or tannin. If the' sound record is printed through the back, a decolourisable yellow or red filter or ultra-violet absorbing layer may be placed between the silver chloride and bromide emulsions, or a yellow or red filter dye or an ultra-violet absorbing substance may be incorporated in the silver chloride layer. Alternatively the silver chloride layer may be sensitized for blue-green, yellow, red infrared or for any light to which the silver bromide emulsion is not sensitive, permitting contact or projection printing of the sound record from the front. The sound record emulsion may be coated only on the border of the film and the remaining space filled by a plain gelatine coating. The binder for the silver chloride emulsion may be collodion, cellulose acetate or ether, or polyvinyl chloride, either alone or with gelatin. The residual silver chloride may be converted into silver ferrocyanide or removed with ammonia. The silver chloride or bromide emulsions may be developed by colour developers giving coloured or black dye images. Reduced Thioindigo Grey, dialkylthioindigo or aminothioindigo may be used or a mixture of p-aminodimethylaniline (the developing agent) and eugenol, isoeugenol, oil of cloves, vanillic alcohol, 1: 2-dihydroxynaphthalene-4-sulphonic acid, 1: 5-dihydroxynaphthalene, 1-(m- or p-nitrophenyl)-3-methyl- 5-pyrazolone, hydrocoerulignone or pyrogallol dimethyl ether. Part of the silver may be left in the image. A sound volume control record may be provided, and may be in a colour complementary to that of the sound track or may be - a fluorescent, phosphorescent, ultra-violet or infra-red absorbing record, or an infra-red or ultra-violet transmitting record if the sound track is infra-red or ultra-violet absorbing. The sound track and volume control record may be in separate emulsions processed by colour development or may be in a single emulsion in which the soft areas are, tanned and coloured. The volume control record may be engraved mechanically and may be filled with black dye. The volume control record may be provided outside the perforations. The sound record may be fluorescent or phosphorescent. The fluorescent or phosphorescent sound record may be applied to the back of the film by imbibition, using naphtholsulphonic acids, hydroxynaphthoic acids, hydroquinilinesulphonic acids or cerium ammonium nitrate. The residual silver chloride may, when the sound record is in a silver chloride emulsion, be converted into a tanning ferrocyanide. The sound image may alternatively be converted into' copper thiocyanate or zinc ferrocyanide and the mordant caused to absorb colourless basic fluorescent or phosphorescent substances. Fluorescent or phosphorescent substances may be added to the celluloid support or coated in layers in front of or behind the support and an ultra-violet absorbing sound record provided. A colour developer producing a phosphorescent or fluorescent dye may be used, or the dndophenols produced by colour development may be split to phosphorescent or fluorescent quinones. The silver bromide of the picture recording emulsions may be exposed in the whole width of the border for the sound track, so that it is removed simultaneously with the silver of the first development. Specifications 427,51,7, 500,716 and 500,826 are referred to. The Specification as open to inspection under Sect. 91 comprises also the subject-matter of Specification 520,173, and also refers to the use of antifogging agents, emulsions sensitized in zones, the printing of a copper ferrocyanide sound record, the X-ray sensitizing of the sound record emulsion with the thorium salt of eosin, the use of a removable waterproof varnish on either the picture or sound areas, the use of a two-layer material of which the lower layer is tanned or is of hardened gelatine, the use of mercuric bromide as the light-sensitive substance for the sound record the use instead of the combination silver chloride-silver bromide of the combinations silver chloride-silver iodide and silver bromide-silver iodide, the use of a material comprising silver bromide emulsions containing colour components and a fourth silver ferrocyanide layer, the use of silver chlorobromide emulsions, the omission of the sound track, the use of anti-halation layers, and the use of the controlled diffusion process. This subjectmatter does not appear in the Specification as accepted.