Photopolymer plates, or Solar plates as they are also known, are used in the Flexographic printing industry. They have also been used by Art Printmakers for many years and this is where I first learned to use them, 20 years ago, when I was working in printmaking, doing etchings and block prints.
Making a Photo Polymer Plate, or PPP, is simple and can easily be done at home, as no harmful chemicals are needed and the equipment used is easily and cheaply obtained.
How to pick the right plate for your work
Plates are available on steel, or with a plastic back and come in different thicknesses, making them suitable for a number of processes, such as Keum-Boo, Enameling and general texture and designs plates
I use steel plates for work that needs fine, or sharp, clean lines, and plastic plates where the design is less demanding, such as master plates for carving, where a lot of work is done to the clay after impressing, or some of my enamel designs, where the lines are thick and bold.
And, sometimes, where very sharp, clean lines, would not be appropriate to the design and I want a more rustic look to the image.
So how do PPPs work?
Solar plates are made up of 3 layers:
1- A steel or plastic backing plate. – the light sensitive polymer layer that will form the impression. This is the layer that hardens where it is exposed to UV light.
– A cover film. This protects the plate and is removed before exposure.
Here’s a brief overview of the process:
After cutting the plate to the required size, you would;
1. Remove the cover film.
2. The artwork, on overhead transparency film, is placed on top of the plate. During exposure, the black areas in the artwork block out the UV light and the plate underneath will remain soft, the clear areas will let U.V. light through and will harden the plate below.
3. Scrub the plate in warm water washes away the soft parts of the plate.
4. Dry the plate and post-expose.
1- Making the Artwork
Artwork should be printed on an overhead transparency, this should be line work, pure black & white, no grey tones unless they had a dot screen applied. Art can be printed on a laser printer at home, or a photo copier. Check to make sure the black areas are solid, no light should pass through, if necessary double up the image.
2- Remove the cover film from the plate’s surface and clamp the artwork onto the emulsion side of the plate, toner side down if possible, cover with a sheet of glass to ensure good contact.
3- Expose the plate for the amount of time recommended by the manufacturer, using a UV light unit. If unsure expose a test strip using different times to see which gives the best results. My own exposure unit takes 1.5 minutes (just as a guide) but some units only take 30 seconds, so test to avoid wasting a large sheet of material
4- Remove artwork and wash the plate in warm, but not hot, water, use a soft nailbrush in a circular motion until desired depth is achieved.
5- Wipe the plate with a chamois or other lint-free material
6- Dry the plate thoroughly with a hairdryer or in front of a heater until completely dry
7- Place the plate back under the UV exposure unit and post expose for the same time you used for the first exposure, this hardens any material that is still soft from the wash-out
8- Brush the plate with olive oil before using it with PMC, fresh plates are ‘stickier’. Store plates away from heat, I like to keep mine standing on edge to avoid warping.