| 摘要 |
1,174,052. Photographic stripping films: photogravure processes. GEVAERT AGFA N.V. Dec.6, 1966 [Dec.9, 1965], No.52372/65. Headings G2C and G2M. A photographic stripping film comprises a hydrophobic polymeric support directly coated with a warm water soluble or permeable stripping layer of a hydrophilic colloid and a synthetic polymeric latex; the stripping layer either containing the light-sensitive material or coated with a warmwater soluble light-sensitive layer either directly or with an intervening warm-water soluble colloid layer and the light-sensitive layer being capable of forming a hardened, warm-water insoluble image by or after imagewise exposure. Specified lightsensitive materials are silver halide and dichromates specified stripping layers are mixtures of gelatine with a butadiene or vinylidene chloride- /acrylonitrile copolymer latex or with a vinylidene chloride/methyl acrylate/ethyl acrylate terpolymer latex. The stripping films are used in the photogravure process and for this process are imagewise exposed to give a hardened image directly (if a bichromated colloid is used) or on development with a tanning developer and contacted with a metal cylinder after being wetted with water and an organic solvent such as an alcohol or acetone. The support is now stripped off, and the unhardened areas washed off and the metal thus based is etched. The binder for the silver halide emulsion may include a latex even when it is not the stripping layer. |
