Verfahren zum Resensibilisieren eines photographischen Materials

摘要

1,199,066. Re-sensitizing de-sensitized photographic silver halide materials. EASTMAN KODAK CO. Nov.23, 1967 [Nov.23, 1966], No. 53371/67. Heading G2C. A chemically de-sensitized photographic silver halide emulsion layer is re-sensitized by treatment with a re-sensitizing agent which is a tetrazole, a triazaindene, a tetrazaindene, a pentazaindene, a pyridine or a cyclic disulphide so as to increase the sensitivity of the emulsion layer at least ten times. The treatment may be effected with an aqueous solution of the agent, or a colloid layer containing the agent may be brought into contact with the wetted emulsion layer. Re-sensitizing agents specified include 4-hydroxy-6-methyl-1:3:3a:7-tetrazaindene, 4-hydroxy-6-methyl-1:2:3:3a:7-pentazaindene, 6-hydroxy-4-methyl-1:2:3:3a:7-pentazaindene, 4-hydroxy-6-methyl-1:3a:7-triazaindene, 3-(γ-carboxypropyl)-1:2-dithiacyclohexane, 5-(3:4-dimethoxyphenyl) tetrazole, 5-(4-cyanophenyl) tetrazole monohydrate, α-picolinium-#-phenylethiodide and pyridine. The chemically de-sensitized emulsion layer is a negative working, developing-out, unfogged emulsion layer which has been de-sensitized to radiation of wavelengths between 1 and 1200 mÁ. by incorporating therein a de-sensitizer which is a heavy metal salt such as mercuric chloride or triammonium hexachlororhodium (III), an anthraquinone dye containing a sulphoalkylaminosulphone radical such as anthraquinone-2-sulphotauride, a non-heterocyclic aromatic compound containing a nitro group such as 3:5-dinitrobenzhydrazide, a heterocyclic compound containing a sulphur or nitrogen in the heterocyclic ring such as 4-nitro- 6-chlorobenztriazole 2-phenyl-1:2:3-benzothiadiazolium bromide or a styryl, cyanine or merocyanine spectral sensitizing dye used in desensitizing amounts, e.g. anhydro-3-ethyl-9- methyl-31-(3-sulphobutyl)-thiacarbocyanine hydroxide. When a sensitizing dye is used, the re-sensitized emulsion layer shows the spectral sensitivity of that dye.