Photopolymer is a process taken from the printmaking world. I use to do t-shirts using the photopolymer emulsion on a silk screen. Instead of squeegeeing ink through a screen to create the finished design, it is used to create a reusable mold. In both instances it is used to make multiples.
Photopolymer plates can be plastic or metal. Both are covered with the light sensitive emulsion and both require the same finishing steps. The plates can be different thicknesses from ones that create a shallow to a very deep design, Plastic plates will warp and harden over time. Metal ones will last longer. Both should be oiled and kept in a cool place after use.
Okay, I've gabbed enough. Here's the process.
Working in a room with very low lighting, place the transparency that contains the desired design on the emulsion side of the plate. (The print should be as dark as possible. Sometimes I tape two prints together.) Create a sandwich by layering a hard piece of backing, a spongy material, the plate with the design on it (if it contains lettering they must read backwards), and a piece of glass. This sandwich is held together by clips which compress everything for the best contact of the plate and design.
The next step uses a UV light (but you can also go outside and dance around in the sun...... if you have some.) I use the light. Place the sandwich (glass side up) in the UV light (be sure not to look in when the light is on.) Time for one minute. Take the sandwich apart and head to the sink to brush the plate with a soft bristle brush. Scrub until the softened emulsion is brushed off. (Brush gently or the design could be lost.) The areas covered with the black design were protected from the light and will wash out. The areas where the light was able to get through will harden and remain. After brushing, rinse the piece to remove stickiness. Pat dry and place back under the UV light to finish curing.
The plate is now ready to be used with the clay.
