Does anyone have a formula for an emulsion that will hold silver, gold, platinum/palladium and gum+gouache to plexi and casting resin in a dry state such that layers of these metals and paint can be applied/dried/contact-printed, then coated and re-registered with subsequent layers (like gum separations) to create a thick slab photograph that has somewhat holographic depth? I believe gum arabic is too weak to maintain this sort of suspension (once put in the water bath) and I don't want to sand down the plexi. The problem with using some clear glue is that I can't wash/develop/fix the layer once exposed. I think I need some semi-permeable emulsion that can stand up to water and harden to take another layer of emulsion. Suggestions?