I regularly use photopolymer sheet to make my own textures for using with metal clay. it is available in a number of thicknesses and also with either a plastic or metal backing. I have a slight preference for the metal backed version although it is easy to cut the plastic backed version yourself with scissors and the plastic backed version is also flexible.
To make your own you need a UV light source, photopolymer sheets, line drawings printed onto transparent sheet a small clip frame i.e.. glass, backing and a bit of white card and some metal spring clips, a soft nail brush (you can buy a specialist sponge for washing the plates). Check that it fits inside the light box before you start. I begin by printing two copies of my line drawings onto overhead projector sheet and then very carefully tape the two layers together to make a double thickness transparency with quite dense lines. Make sure you line the layers up really carefully.
Unwrap your piece of light sensitive photopolymer sheet and remove the thin protective layer (wrap any unused sheet back up in black plastic straight away). Place the transparency onto the photopolymer sheet and put it on a small sheet of white card on top of the back board of a clip frame. Place the glass on top and clip the layers together so they are held firmly against each other. Remember that the black areas and lines are the areas that are washed away and if you are using text you will want the finished plate to have the text in reverse.
Place it in the UV box and switch on – you may want to do a test piece first by covering most of the sandwich with a card and drawing it out a little every five seconds, so that you have even segments of your test piece with different exposures. Then when you wash, dry and finish the plate you will know the best exposure time for your set up. I know that mine works best with an exposure around 25 seconds. Set a timer so that you know you are making consistent exposures. Do NOT look into the UV light. Mine is a UV nail box but you can purchase a professional version if you really like using this technique.
Once the exposure has been completed take the photopolymer sheet out of the stack and wash it gently in hot water. I use a very soft natural bristle nail brush but you can get a special sponge from most photopolymer suppliers. Be careful not to over wash your plate at this stage. It will be tacky so dry it thoroughly either with a hair dryer or in a dehydrator. You can wash it right down to the backing plate but I generally prefer not to. Then re-expose your plate in the UV light box without the glass this time. I usually give mine a minute. This sets the areas that weren’t exposed the first time.
Remember to lightly brush olive oil or release agent over your sheet before each use and I keep them wrapped in acid free lightly oiled tissue paper in a box when not being used. If clay does accidentally stuck into your plate you can give the plate a gentle wash and dry to clean it up. I hope you enjoy creating your own unique texture plates – they can of course be used for printmaking too!