PRESS: Preliminaries for polyester
When running polyester plates on a Printmaster GTO 52 with a direct continuous dampening unit, do not thin the ink with print oil or other additives. Keep the water pan spotless so that no grease gets onto the plate. The dampening system’s pH value should be about 5. (Important: do not add alcohol.)
To avoid overstretching the plate during mounting, tighten the tensioning nuts only by hand. Compression between the blanket and the plate cylinders must not exceed .1 mm.
Before production, polyester plates must be treated with the sponge-on etching solution recommended by the manufacturer. If printing is interrupted, more etching solution should be applied; or, if appropriate, the plates should be pre-dampened by letting them run several revolutions with the setting “dampening system on” before printing resumes.