Patent GB-555383-A (GB)
Title: Improvements relating to photographic stripping films
IPC: G03C1/805
Filed: 1941-12-05
Abstract: 555,383. Photographic stripping film. KODAK, Ltd. (Eastman Kodak Co.). Dec. 5, 1941, No. 15729. [Class 98 (ii)] A photographic stripping film has a permanent support bearing a sensitive photographic emulsion and having a back surface of a cellulose ester, which permanent support is united at its back with a temporary support having a front surface of a cellulose ester of different constitution by means of water-insoluble adhesive which is compatible with the surface of one of the supports but not with the surface of the other. The permanent support may be of cellulose nitrate, acetate, acetate-propionate, or other ester, the temporary support of cellulose nitrate, acetate, acetate-propionate, acetate-butyrate, or paper, including cellulose nitrate or paper coated with a layer of cellulose organic acid ester, and the adhesive a cellulose ester (e.g. acetate or acetatepropionate), a cellulose ester (e.g. ethyl cellulose), a natural or synthetic resin (e.g. shellac, copal, rosin, sandarach, an acrylate, or a vinylite), or a wax (e.g. Carnauba wax). The adhesive is preferably water-insoluble. The surface of each support and the adhesive are preferably all of cellulose ester, e.g. the surface of the temporary support may be of well-esterified ester, and the adhesive and the surface of the permanent support of substantially hydrolyzed ester. The adhesive may be applied to the temporary support and a solution of the cellulose ester or other substance to form the permanent support applied to the adhesive. One or more subbing layers may be applied prior to the application of the emulsion. The temporary support (or its surface) is preferably of well-esterified cellulose ester, e.g. cellulose acetate of 38-42 per cent acetyl, cellulose acetate-propionate of 30-32 per cent acetyl and 16 per cent propionyl, or cellulose acetate-butyrate of about 31 per cent acetyl and 20 per cent butyryl. The adhesive is preferably a wellhydrolyzed cellulose ester, e.g. cellulose acetatepropionate of 20 per cent acetyl and 15 per cent propionyl, which is incompatible with the temporary support. The adhesive layer may be formed by applying a solution of cellulose acetate-propionate in ethylene dichloride, ethylene glycol monomethyl ether, acetone, and methanol to the temporary support. With a suitable adhesive, the cellulose ester of the temporary support may have a lower acetyl content than that specified above. The permanent support may be formed by applying a solution of cellulose nitrate in n-butanol acetone, ethylene glycol monomethyl ether, and methanol, or a solution of cellulose acetate or acetate-propionate in acetone, ethylene glycol monomethyl ether, and methanol. The permanent support may be subbed with gelatin or a mixture of gelatin and synthetic resin, and a gelatino silver halide emulsion layer applied. In making a colour correction mask, the permanent support is after stripping cemented to a colour film by means of a composition containing gelatin, glycerin, Turkey red oil, glacial acetic acid, and water. The emulsion of the stripping film is exposed through the colour film and processed. The colour film and stripping film may be cemented support to support, emulsion to support, or emulsion to emulsion. If the stripping film emulsion is to be processed after cementing, this emulsion should be accessible to processing liquids. The stripping material may be bound in contact with the colour film and exposed through the latter as in Specification 537,696, and stripped after processing and cemented in register to the colour film. A sound track may be printed in in the stripping film emulsion before or after cementing, or it may be printed in a further stripping film applied to the colour film. The stripping film may be used to apply a sensitive emulsion to a metal or other surface by stripping and applying the permanent support to the metal or other surface. Specifications 357,817, 366,380, 537,864 and 554,300 also are referred to.