Process for developing positive photosensitive lithographic printing plate

摘要

PCT No. PCT/JP81/00247 Sec. 371 Date May 18, 1982 Sec. 102(e) Date May 18, 1982 PCT Filed Sep. 21, 1981 PCT Pub. No. WO82/01086 PCT Pub. Date Apr. 1, 1982.A developing process suitable to treat a positive photosensitive lithographic printing plate comprising a photosensitive layer containing, as the photosensitive constituent, an o-quinonediazide compound provided on an aluminium plate. A positive photo-sensitive lithographic printing plate is exposed imagewise and then developed with a developing solution containing an aqueous solution of an alkali metal silicate in which the alkali metal is essentially constituted by potassium. With the method, development treatment can be conducted stably for a long period without generating insolubes in the developing solution even when an extremely large quantity of positive photosensitive lithographic plates are treated.