PHOTOCHEMICAL RECORDING USING HEXACYANOFERRATE(III) IONS

摘要

1,204,665. Photo-sensitive material. GEVAERT-AGFA N.V. Dec.12, 1967 [Dec.15, 1966 (2)]; Nos. 56294/66 and 56295/66. Heading G2C. [Also in Division H1] A light-sensitive layer comprising (i) a ferricyanide, (ii) a substance capable of yielding Zn, Cd, Hg, Cu, Ag, An and/or Pb ions, and optionally (iii) an n-type photo-conductor as sensitizer is developed after imagewise exposure with a solution of a cationic dye, the dye being preferentially mordanted by the ferrocyanide produced in the exposed areas. Preferably the developer is acidic and contains a triarylmethane or thiazine dye, a swelling agent (e.g. urea or an organic solvent), and a surfactant. The lightsensitive composition may be absorbed in a paper support or dispersed in a binder (e.g. urea- HCHO resin, copoly vinyl acetate/vinyl laurate or gelatine). The photo-conductor is preferably ZnO or TiO 2 containing a sensitizing dye and/or dopant (e.g. Al and/or Cr ions). The metal ions may be provided by a sparingly water-soluble salt or by a metal or compound which reacts with acidic developer to form an ionic salt. An alkalimetal ferricyanide stabilized by an oxidizing agent (e.g. a dichromate) is preferably used as (i).