I was wondering if anyone had any insight into this question.  Let me give you some background first.  I am doing cloisonne on copper.  I am also torch firing the entire piece.  First, I curve and counter enamel the piece.  Next, I paint the front with holding agent and place the cloisonne wire (rolled fine silver) and sift opaque white enamel and then fire with a torch from underneath.  From there on out I add transparent enamels and finish with an alundum stone and a final layer of clear. 
My question is this: I am looking for a way to add texture to the opaque white layer that will show through the transparent layers.  I haven't tried anything yet so I am open to any suggestions you may have.  Please let me know if you have any techniques or tricks that may help.  Thank you in advance.
Warmly,
Erin Brown

Erin, I would suggest sifting the opaque white onto the copper and firing it before the cloisonne wire is put on so your cloisonne wire doesn't get in the way when you're texturing the white enamel. An added advantage is that the wires will be held in place better if there is enamel under them rather than just around them. You can either texture the white enamel before firing it with sgraffito (scratch or draw a texture in the enamel, then fire), or you can fire the white enamel and use a dremel kit or flex shaft with a diamond bit to etch a texture into the white enamel. The diamond bit will also texture the copper, so that may actually look more interesting than the sgraffito. Once the white enamel is textured and fired, you can place your wires, add a layer of transparent and fire until the white enamel re-fuses and holds the wires. If the white is harder fusing than the transparent, put a little bit of white enamel where you can see it so you know it's fused again. Good luck!

Erin, look at the book by Margaret Seeler, who did enamels with an opaque under transparent color in cloisonne. She would wet-inlay it to 'sculpt' the high and low levels in figures so as to achieve modeling of the forms. High places of light op. would be nearer the surface of the trans. over-colors, to show up as musculature. The deeper layer of transparent appears darker in tone. This is the shadow of the modeling. I have done it in a small portrait, now gone, with nice results. So put down the sifter and wet inlay varied heights of opaque cream, or ivory, or white. Just be certain to dry it completely. A slower fusing or 'hard' opaque works best, to avoid too much flow to level. Don't fire it completely level, or it is lost as modeling. Then sift or lay in layers of medium fusing trans color. Stone or grind level and flash fire.

Erin-one way to add texture is to roller print it into a sheet of fine silver (or gold) enameling foil. These sheets are very thin, so you won't need a lot of pressure & you need to sandwich the sheet between something that will release it when you want to use it. There are many ways to contour the impression-from layered paper to tooled metals. Ricky Frank could detail this process better than I can remember. One can imply texture via thin clumping of other colors of enamel or you might add enamel threads on top of the white. Just some ideas. Steve Artz is also a good person to ask & Coral Shaffer. Eileen