Developer for light-sensitive lithographic printing plate capable of processing commonly the negative-type and the positive type and developer composition for light-sensitive material

摘要

There are disclosed an aqueous alkaline developer for light-sensitive lithographic printing plate commonly processing a negative-type light-sensitive lithographic printing plate having a light-sensitive layer containing a diazo compound and a positive-type light-sensitive litho­graphic printing plate having a light-sensitive layer containing an o-quinonediazide compound, which comprises containing an alkali agent, 0.1 to 10 % by weight of a water-soluble reducing agent, a sodium, potassium or ammonium salt of an organic carboxylic acid, and a non­ionic or cationic surfactant, and having a pH in the range of 12.5 to 13.5, and also a developer composition for light-sensitive material, which comprises an aqueous solution containing a compound represented by the formula (I) shown below:     wherein R₁ represents an alkyl group or an alkoxy group each having 2 to 5 carbon atoms, or a hydroxy­alkyl group having 2 to 5 carbon atoms; and R₂ repre­sents a hydrogen atom, a halogen atom, an amino group, a hydroxyl group, an alkyl group, an alkoxy group or a phenyl group.