Platemaking Problems

Despite advances in plate technology, problems in the platemaking process occur. We have seen some of these in our platemaking/processing system.

Scumming and tinting - occurs when nonimage are accepts a layer or uniform tint of ink. Can result from several sources. Fogging when negative working plates are exposed to daylight or room light. We have seen this on some old plates have been fogged because of exposure from frequent opening and closing of drawers.

Incomplete development may lead to small amounts of residual coating on plate which causes scumming on press. May be remedied with second pass through processor.

Note that this doesn’t help with fogging since the pre exposed area is already hardened and impervious to processor solution. Too much ink dissolved or dispersed in dampening solution.

Caused by too high of pH. Insufficient gum on plate. Plates should be gummed on press when the press is down for more than 30 minutes.