Polymer Plate FAQs

What are the correct exposure times for your polymer plates?

• Exposure time varies greatly by exposure unit. With our Autolight Exposure Unit, start with 60 seconds on the first exposure and 60 seconds on the second exposure (film positive)
• Exposure time depends on the quality of film positives. Pass a white paper behind the film positive. If you can detect the edge of the paper behind the emulsion, your positive is somewhat transparent and will require reduced exposure times. In a good positive, no light should be seen through the black part of the film.

What is the difference between alcohol wash and water wash plate material?

• The difference is in the way the plates are developed: with water or with alcohol. Generally, alcohol wash plates are harder and provide easier control over etch depth. And water wash plates don’t require the use of chemicals.

How many impressions can I get from a polymer plate?

• It varies, but a good rule of thumb is 10,000 – 20,000 impressions for standard polymer plates and 50,000 for premium material.

What is screen film used for?

• The screen is used to control the dot size and the depth of the printing plate. Screen film is used to put dots on the print area – to control the ink volume. (In the second exposure to control ink transfer.) Smaller dots are used for fine text and large dots for bolder logos.

What is scooping?

• Scooping is when your ink cup or doctor blade dips into the large reverse areas of the etch (bold images) and “scoops” out ink. Scooping results in a light spot in the print. This usually can be prevented by placing larger dots to support the cup or blade as it goes over the image.