Pretreatment liq. for correcting photosensitive diazo layer - on litho plate contg. glycerol, phosphoric and hydrochloric acid and dextrin, dextran or PVA

摘要

Pretreatment liq. for correcting adjusting marks, coloured marks, etc. on photosensitive diazo layers on (offset) litho plates is in the form of a soln. contg. glycerol, phosphoric acid and HCl, which also contains 5-15% dissolved dextrin, dextran and/or dissolved PVA. The liq. pref. contains 8-12% dextrin, dextran and/or PVA, 55-65% glycerol and 37-23% of an aq. soln. contg. 49.25-73.9 g/l P2O5 and 3-10 g/l HCl. This liq. does not cause the correcting agent to flow out, so that very fine precise correction of the printing plate is possible and hence printing satisfying the highest quality requirements can be made.