Abstract: 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 non-ionic 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: ##STR1## wherein R.sub.1 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 R.sub.

Abstract: An apparatus for processing an imagewise exposed pre-sensitized lithographic printing plate which entails uniformly applying a desired amount of developer, that has not been substantially used to the surface of the printing plate by a developer supply member comprised of two plates and having a slit at the lowermost portion thereof which contacts the surface of the printing plate, and then transferring the plate containing the developer to a developer storage tank, immersing the plate in the developer storage tank, and removing the developer from the plate.

Abstract: A method of processing an imagewise exposed pre-sensitize lithographic printing plate which entails uniformly applying a desired amount of developer, that has not been substantially used to the surface of the printing plate by a developer supply member comprised of two plates and having a slit at the lowermost portion thereof, and then transferring the plate containing the developer to a developer storage tank, immersing the plate in the developer storage tank, and removing the developer from the plate.

Abstract: A light-sensitive composition for use in the preparation of positive-type light-sensitive lithographic printing plate which comprises an o-naphthoquinone diazide compound and novolak resin in which the novolak resin comprises two different novolak resins each being prepared by the polycondensation or co-polycondensation of an aldehyde with at least one compound selected from the group consisting of phenol, m-cresol, o-cresol and p-cresol.