Patent GB-554301-A (GB)
Title: Improvements in photographic materials
IPC: G03C1/74
Filed: 1941-09-10
Abstract: 554,301. Photographic material KODAK, Ltd. (Eastman Kodak Co., and Lane, G. T.). Sept. 10, 1941, No. 7154/43. Divided out of 554,292. [Class 98 (ii)] Photographic material having a silver salt emulsion layer containing a latent image and carried on a support A is made by taking a sensitive material comprising a dried sensitive silver salt emulsion layer (in which the latent image has been formed) held on a temporary support B by means of an intermediate layer capable of allowing the sensitive layer to be stripped therefrom and causing the outermost surface of the material to adhere to the support A and simultaneously or subsequently stripping the support B and the emulsion layer apart by mere force at ordinary temperature without dissolving or softening the intermediate layer. Dry-stripping material in which the stripping layer is a hydrophobic layer is preferably employed. In a modification, the stripping material is caused to adhere on its innermost surface to the metal or like support after stripping the temporary support. A dry-stripped sensitive paper of which the sensitive layer is a gelatino-silver halide emulsion which is first stripped for a few inches from one end and the so-stripped emulsion layer is caused to adhere to the metal sheet on the same side of the emulsion layer as that which was nearest the paper support so that on continuing the stripping action the remainder of the emulsion layer can be continuously adhered to the metal as the stripping proceeds. Alternatively, the emulsion side of dry-stripping material is caused to adhere to the metal and the temporary support dry-stripped therefrom. The permanent support transferred with the emulsion is removable in or permeable to the developer. The metal sheet or other support may be coated with an adhesive layer or a layer which can be rendered adhesive by heat or by treatment with a softener before the emulsion is caused to adhere thereto. Alternatively, an adhesive layer or a layer which can be rendered adhesive may be coated on the sensitive side of the stripping material, and a varnish layer on the metal. An adhesive layer or a layer which can be rendered adhesive may be coated both on the emulsion and on the metal. Supports other than metal are concrete, hard sheets of resin or cellulose esters, or tracing cloth. The adhesive layer may be softened by applying a mixture of a solvent and non-solvent or a plasticizer composition. The dry-stripping material may have a paper support, a stripping layer of wax or resin, and an emulsion layer, no layer being interposed between the stripping and emulsion layers. In an example, paper is coated with a solution of beeswax in trichlorethylene, then with a process emulsion, and finally with a lacquer comprising cellulose nitrate, ester gum, di-n-butyl phthalate, and formamide dissolved in acetone, n-butyl acetate,, n-butyl alcohol, and amyl acetate. Anodized polished aluminium is coated, e.g. by spraying, with a lacquer comprising cellulose nitrate, ester gum, and di-n-butyl phthalate dissolved in ethyl acetate and n-butyl acetate, When dry, the paper is applied to the metal, lacquer surface to lacquer surface, a softener solution being applied to one or both surfaces (e.g. a mixture of industrial spirit and ethylene glycol monomethyl ether). The paper may then be stripped from the metal. When transferred to a grained metal plate for photolithography, a low melting-point emulsion is employed. The sensitive layer may contain a matting substance, or a matt layer may be coated over it, to facilitate writing upon it. The metal may be rendered non-corrosible by treating in a bath containing phosphoric acid or by coating with black lacquer. The image may be produced in a light-coloured substance, e.g. AgI. Alternatively, a white or coloured lacquer may be coated on the metal, and the image produced in a dark or coloured substance. The lacquer may contain a fluorescent or luminescent substance and the material employed as in Specification 548,795. The temporary support may be opaque or coloured to protect the emulsion, and need not be stripped until just before use. Specifications 549,371 and 553,341 also are referred to.