Patent GB-546559-A (GB)
Title: Improvements in photographic materials
IPC: G03C1/76
Filed: 1941-01-13
Abstract: 546,559. Photographic sensitive material. KODAK, Ltd. (Eastman Kodak Co.). Jan. 13, 1941, No. 479. [Class 98 (ii)] Photographic sensative material (films, plates, papers, or tracing cloths) is coated on one side with a photographic sensitive emulsion and on the other side with a layer comprising a mixture of a hydrophilic binder, a water-insoluble binder, and an inorganic pigment, this layer being adapted to receive ink and pencil markings. The sensitive material may have a waterproofed paper or cloth support, which may be obtained by applying a coating of cellulose nitrate or other cellulose ester to each side of the support. A gelatinecontaining substratum may be applied to one side, followed by application of the emulsion layer, Alternatively a substantially water-resistant cellulose ester support may be employed, and a gelatine-containing substratum applied to both sides. The pigment may be titanium oxide, baryta, chalk, or lithopone. The hydrophilic binder may be gelatine, and the water-insoluble binder a cellulose organic or inorganic ester (such as cellulose nitrate, acetate, or acetate-propionate), or a cellulose ether or a natural or synthetic resin (such as polyvinyl resin). In an example, the paper is waterproofed by applying cellulose nitrate to each side, applying a gelatine subbing layer followed by a gelatino-silver-halide emulsion layer to one side, and applying to the other side a pigmented layer using a coating solution containing cellulose nitrate, gelatine, acetic acid, water, acetone, methanol, and titanium oxide. A different cellulose ester may be used on each side of the paper. The paper support may be previously coated with a gelatine layer containing baryta. A waterproofing layer of cellulose acetate or acetate-propionate may be followed by a substratum layer containing gelatine and synthetic resin or gelatine coated from a solution in water, acetic acid, acetone, and methanol. Two waterproofing layers may be interposed between the support and the pigmented layer. If the pigmented layer contains a cellulose ester other than cellulose nitrate, the subbing layer may contain a synthetic resin. A cellulose acetate support may be coated with cellulose nitrate on both sides before applying the subbing layers. In a further example, a thick glossy paper coated on one or both sides with a caryta-containing gelatine layer is coated on both sides with a cellulose nitrate layer from a composition containing cellulose nitrate, amyl acetate, methanol, acetone, and triphenyl phosphate. A second thin coating of similar composition is applied to one side (the side not coated with baryta, if only one side is so coated), followed by a coating containing cellulose nitrate, gelatine, and titanium oxide. On the other side is coated a gelatine substratum layer followed by a gelatino-silver-halide emulsion layer. The material may have several differentially-sensitized emulsion layers for colour photography. The emulsions may contain light filter for sensitizing dyes or colour formers. Silver bromide, chloride or chlorobromide emulsions may be used. Specifications 477,153, 477,289 and 478,357 are referred to.