| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for making a planographic printing plate in which both stain in printing and printing resistance are ensured without impairing image forming property, a developing solution can be stabilized and even processing stability is improved. SOLUTION: In the method for making a planographic printing plate, an original plate for the planographic printing plate having a photosensitive layer comprising a polyurethane resin binder, a compound having an addition polymerizable ethylenically unsaturated bond and a photopolymerization initiator on an aluminum support is imagewise exposed with laser light and developed with a developing solution containing an alkali silicate and a nonionic compound of the formula (I): A-W (where A is a hydrophobic organic group in which the logP of A-H is >=1.5 and W is a nonionic hydrophilic organic group in which the logP of W-H is <1.0) and having an SiO2 to M2 O molar ratio (M is an alkali metal or ammonium) of 0.75-4.0, pH 11.5-12.8 and 3-30 mS/cm electric conductivity. |
