| 摘要 |
<p>998, 954. Photographic materials; photomechanical printing surfaces. MITSUBISHI PAPER MILLS Ltd. Oct. 19, 1961 [Oct. 19, 1960; Aug. 18, 1961], No. 37582/61. Headings G2C and G2M. A photographic film base comprising a polymer or copolymer of vinyl chloride vinyl acetate, acrylonitrile or vinylidene chloride or polyethylene terephthalate, or a paper, cloth or fibre sheet impregnated or coated with such a polymer or copolymer, is subbed by coating it with a solution of a vinylidene chloride polymer or copolymer in a mixture of 70-50% by volume of an aromatic hydrocarbon and 30-50% by volume of a ketone, drying in a current of air at 50-85‹F. and 80 10% relative humidity at an air speed of 0. 5-4 m./sec. to give micro holes over the surface of the layer, and is then coated with a photosensitive layer or a receiving layer containing nuclei for the silver salt diffusion process. The photosensitive layer may be a silver halide emulsion layer. The reverse side of the base may be coated with a hydrophilic anti-curling layer which may contain an antihalation dye. The vinylidene chloride for the subbing layer may be copolymerized with vinyl chloride or acrylonitrile. In Example 2 the reverse side of the film base is coated with an aequous dispersion of a polyvinylidene chloride, a watersoluble colloid and rice starch. Photographic material according to the invention comprising a silver halide emulsion layer can be turned into an offset printing master by exposing and developing to give a positive right-hand image, etching the wet film in an aqueous solution of cupric sulphate, citric acid and potassium bromide to which hydrogen peroxide has been added, lightly scrubbing with wet cotton and washing in dilute acetic acid.</p> |
