In response to a question in a comment, here’s a video from the show Beads, Baubles and Jewels, that shows you how to make a photopolymer plate (PPP).

Where can you buy photopolymer plates?

Art Clay World

Boxcar Press

and here are links to more resources on the blog:

How to cut steel backed plates, a video from Sue McNenly

Improve Your Photopolymer Plates with this Tip

and here’s a post from me from 2007:
Getting Started with Photopolymer Plates