| 摘要 |
893,808. Photographic developing processes and apparatus. CONSOLIDATED ELECTRODYNAMICS CORPORATION. Feb. 15, 1960 [Feb. 17, 1959], No. 5232/60. Drawings to Specification. Classes 98(1) and 98(2). A method of rapidly developing a silver halide photosensitive emulsion with an alkaline developer solution containing a thermally unstable ammonium compound and/or a compound which produces an acid gas on heating comprises wetting the emulsion with a film of the developer solution and thereafter heating the wetted emulsion to decompose the ammonium compound and / or produce said acid gas in order to lower the pH of the solution on the emulsion, whereby the developing activity of the solution is decreased. Alternatively, if the alkaline developing solution contains a thermally unstable ammonium compound which decomposes at one temperature and the emulsion is disposed on a support containing or carrying a compound which produces an acid gas on heating to a higher temperature, the method may comprise wetting the emulsion with a film of the developer solution, thereafter heating the wetted emulsion to decompose the ammonium compound and lower the pH of the solution on the emulsion, whereby the developing activity of the solution is decreased, and thereafter heating the support sufficiently to decompose the acid-gas-producing compound. The developing solution may for example contain a mixture of Phenidone and chlorhydroquinone, and the thermally unstable alkali may comprise ammonium hydroxide, a mixture of a thermally stable alkali such as caustic soda or sodium carbonate and an ammonium compound such as ammonium chloride, or a substituted ammonium compound such as the quaternary ammonium hydroxides-for example tetraethyl ammonium hydroxide, tetramethyl ammonium hydroxide, and other in which the hydrogen atoms are replaced by various combinations of methyl, ethyl, butyl, and hexyl groups. The acid-gasproducing compound may comprise a sulphite, sulphate, or carbonate of zinc, tin, lead or mercury-preferably zinc sulphite-or a hydrochloride of a high molecular weight stable organic base such as cyclohexylamine hydrochloride or its higher homologues. The emulsion may, if desired, be wetted with developer before exposure, and if it is intended to keep the recorded information for future reference, the emulsion may later be fixed or stabilized in conventional manner. The Specification also describes and illustrates an apparatus in which a roll of photographic recording paper is fed past an exposure window, through a developing section in which a thin film of developer is applied to the paper, over a heating plate, and finally out of the apparatus for observation. Specification 888,700 and U.S.A. Specification 2,983,250 are referred to.
|
