GB535374A - Improved anti-static photographic film - Google Patents

Abstract

535,374. Photographic films. KODAK, Ltd. (Eastman Kodak Co.). July 7, 1939, No. 19819. [Class 98 (ii)] A photographic film comprises a support and a sensitive layer thereon in which the sensitive layer has applied thereto a layer consisting of a colloid binding agent and an inert material or contains such agent and material, the diameter of the particles of the material being not more than 0.01 mm. and the particles of the material providing 20 to100 minute irregularities per square mm. of film surface. The film may comprise a support and a sensitive layer thereon to the front surface of which sensitive layer has been applied a layer of a colloid binding agent containing a finely divided inert material in the form of particles in quantities sufficient to produce minute irregularities in the surface but insufficient to render the film visibly matte. The particles may be of silica, starch (particularly rice starch), resins (such as polymethyl methacrylate, polyvinyl acetate, polyvinyl alcohol, co-polymers of styrene and methyl methacrylate, and mixtures of polyacrylate resins with cellulose ethers, and cellulose derivatives (such as cellulose acetate propionate and ethyl cellulose). The support may be cellulose ester or paper. The substance may have a refractive index approximately the same as the material of the layer and may be soluble or removable in the processing baths. The particles may also be added to a fine-grained sensitive emulsion to be applied over a substratum of ordinary type. According to the Provisional Specification a roughened surface may be produced by passage over sand-blasted or embossed rolls. Matting substances may be incorporated in the support itself. The layer may be applied as a substratum or to the rear of the support. One or both sides of an X-ray film support may be so coated prior to emulsion coating.