GB716529A - Improvements in or relating to photographic films having a lenticular grating - Google Patents

Abstract

716,529. Lenticular film for photographic use. CIBA Ltd. July 18, 1952 [July 19, 1951], No. 18266/52. Drawings to Specification. Class 98(2) A cellulose ester film with a lenticular grating on one side is surface hydrolysed and also provided with a layer as of gelatin or polyvinyl alcohol on the other side. Such gelatin layer may have a lenticular grating which optically corresponds to the first mentioned grating. An intermediate layer of hardened gelatin may lie between the hydrolysed surface and the lenticular gelatin layer. In preparation the first lenticular grating may be produced by embossing, or casting of the film using a lenticular surface as mould, the hydrolysed layer formed by application of aqueous alcoholic alkali to the non-lenticular side and the gelatin layer or layers applied thereover, with bichromate sensitization of the outermostgelatin layer and production of lenticulations therein by exposure through the first lenticular 'grating and washing as described in Specification 682,853. The The film, still not sensitized for image production, and whether it has a grating on one side only or on both sides, may now be sensitized by application of an acid solution containing a complex ferric salt and a silver salt, and, desirably, also a dyestuff to restrain the action of exposing light as described in Specification 701,529. Exposure and development of such film by the method of Specification 701,529 provides the unexpected result that picture formation is confined completely or to a great extent to the hydrolysed layer, and definition is improved by reason of the small thickness of such layer. The intermediate layer of hardened gelatin referred to above is present for the purpose of restricting penetration of the bichromate sensitizer, used for production of the second lenticular layer, into the hydrolysed layer. An aqueous solution containing ferric ammonium citrate, silver nitrate, citric acid. the monoazo dyestuff from diazotized 1-amino-benzene-4-sulphonic acid and 1-phenyl-3-methyl-5-pyrazolone-2':5'-disulphonic acid, and a wetting agent is exemplified as sensitizer for image production.