The plate material is UV photosensitive and has to be kept in the dark until ready to be used. A high contrast negative is printed on a clear transparency sheet and this sheet is placed on the plate, then exposed to UV light and finally washed with plain water. The unexposed portions of the negative (the black areas) will wash out leaving a recessed area in the shape of the blackened areas.
Metal clay is rolled out onto the PPP plate. The recessed areas of the plate now project from the clay and the opposite areas are now recessed. The finished plates have to be kept oiled and in a dark area. The polymer plates can become brittle over time and can break. Some of the plates come mounted on a metal plate and these don't seem to bend like unmounted plates do.
The PPP plates are a perfect mold for creating the inlay designs with copper and bronze clay so I pulled out my collection of plates and gave a few of them a try. The photos here show some of the variety of finishes and clays I've used with a PPP plate.
Here is the exposed PPP plate. This design was based on a necklace I fashioned after an Ojibway Indian Design. The original necklace was loosely based on the design and this earring design was taken even farther.
The first earrings made with the plate were silver. I actually made two pair and colored both pair with enamel. (Sorry but the picture isn't the best.)
I used silver again when I used the plate for the third time. This time I just polished them up and added a patina.
Yesterday, I tried using the copper and bronze inlay technique with the plate.
It's interesting how different a look each pair gets just by using a different metal or a different coloring technique.