Abstract: A method for the preparation of a planographic printing plate wherein a sheet material, which comprises an exterior hydrophilic colloid layer having concentrated on its surface a silver image formed by the silver complex diffusion transfer process with NiS or mixed crystal NiS.Ag.sub.2 S development nuclei in which the molar ratio of NiS to Ag.sub.2 S is not smaller than 1:1, is treated with a liquid for hydrophobizing the silver image for planographic printing, such liquid containing in dissolved state a heterocyclic compound corresponding to one of the following tautomeric structures (A) and (B) or (C) and (D): ##STR1## wherein: R.sup.1 represents hydrogen, amino or acylamino,R.sup.2 represents an alkyl group, andR.sup.3 represents an alkyl group, or an alkanamido-arylene group.

Abstract: Process for the production of a planographic printing plate by means of the silver complex diffusion transfer reversal process comprising the steps of:image-wise photo-exposing a silver halide emulsion layer; developing the resultant latent image in the presence of a silver halide complexing agent and contacting the exposed silver halide emulsion layer with an anodized aluminium platecharacterized in that the thickness of the anodized surface layer is in the range of 0.50 to 2.00 .mu.m, the anodized plate before contact of the same with the emulsion has been hydration-sealed in the temperature range of 60.degree.-80.degree. C., and the development of the light-sensitive material is carried out with a developing composition having a pH of at least 12, and containing:dissolved sulphite,dissolved thiosulphate, anda mixture of hydroquinone and at least one secondary developing agent of the class of 1-phenyl-3-pyrazolidinones and p-N-methylaminophenol.