POSTTREATMENT OF LITHOGRAPHIC PLATE REQUIRING NO DAMPENING WATER

PURPOSE:To obtain a print having a sufficient ink film thickness, by forming a nonadhesive material layer on all the lithographic plate requiring no dampening water using a silicone rubber layer as a nonimage part, and removing only the nonadhesive material layer on image lines to leave deep recesses. CONSTITUTION:A soln. contg. a linear organopolysiloxane having the formula (R is 1-10C alkyl, phenyl, vinyl, and preferably, >=60% of it is methyl) as a main component and various cross-linking agents, and capable of cross-linking and hardening is coated on all the surface of a lithographic plate requiring no dampening water using a silicone rubber as a nonimage part in 1-10mum dry thickness, dried, and heat-treated at about 120 deg.C for 3min. The plate is softly rubbed with absorbent cotton soaked with a solvent to remove the silicone rubber layer only on the image lines, thus permitting the silicone rubber layer on the nonimage part to be strongly adhered, durable deep recesses to be formed, and a print having sufficient ink film thickness to be obtained.