Method for making a lithographic printing plate according to the silver salt diffusion transfer process

摘要

The present invention provides a method for making a lithographic printing plate according to the silver salt diffusion transfer process comprising the steps of: image-wise exposing an imaging element comprising in the order given on a hydrophilic surface of a support (i) an image receiving layer containing physical development nuclei and (ii) a photosensitive layer comprising one or more silver halide emulsions being in water permeable relationship with said image receiving layer (b) applying an aqueous alkaline solution to the imaging element in the presence of (a) developing agent(s) and (a) silver halide solvent(s) to form a silver image in said image receiving layer, (c) treating the imaging element to remove the layer(s) on top of said image receiving layer, thereby uncovering said silver image formed in said image receiving layer, characterized in that said aqueous alkaline solution contains thiosulphate salts in an amount ranging from 0.000 mole/l to 0.0015 mole/l and inorganic bromide salts in an amount from 0.000 mole/l to 0.0030 mole/l and an aminoalcohol in an amount ranging from 0.1 ml to 10 ml/l and that the total amount of the silver halide in said one or more silver halide emulsions (expressed as AgNO3) is not more than 2 g AgNO3/m2.