Showing papers by "Edwin H Land published in 1954"

Photographic processes and compositions useful therein

Abstract: 837,972. Photographic processes. INTERNATIONAL POLAROID CORPORATION. Aug. 20, 1956, No. 25382/56. Drawings to Specification. Class 98(2) A print is produced from a photosensitive stratum including silver, ferric or diazo material, and another stratum by a processing composition in the the form of an emulsion provided by dispersing liquid droplets imparting high viscosity as an internal phase into an external phase comprising an aqueous solution of a developer. Normally the processing composition is spread between the strata, if desired from a rupturable container, and it may be intended to produce a print in the photosensitive stratum only or in the other stratum as well, after which the strata are separated. In two specific examples of the latter procedure the photosensitive stratum comprises a high speed gelatine iodobromide emulsion, the other stratum lead sulphide dispersed in a siliceous vehicle, and the compositions (I) sodium sulphite, sodium hydroxide, sodium thiosulphate and hydroquinone dispersed in a diluted proprietary mineral oil emulsion, and (II) the first four of these ingredients together with turpentine and sodium carboxymethyl cellulose. The internal phase may also comprise volatile or non-volatile, drying or non-drying liquid droplets and various liquids, and plastic materials to be dissolved therein, are quoted, as also are a wide variety of materials for use in the external phase, these including potassium ferricyanide and ferrocyanide, tannins. #-naphthoquinone sulphonic acid, and silver, platinum and palladium salts for image production in the case of the ferric sensitizers, and couplers described simply as phenols, naphthols and amino compounds for the diazo materials. Specifications 684,592, 703,231, 732,420, 751,304, 776,634, 789,837 and 811,579 are referred to.