No two resin pieces are ever the same, even when made at the same time using the same colors. Temperature, moisture, paint density and the cure rate of various colors will affect the final product.
I work with cradled wood panels in various sizes as the substrate for my resin art because it is less likely to sag under the weight of the resin. I color my resins with acrylic paints, mica pigments, powdered metal leaf.
I have tried various resins but primarily use MasterCast 1-2-1 Clear Art Coating Resin because it has been ASTM certified non-hazardous and non-toxic. MasterCast is a two-part epoxy resin that self- levels. Once cured, MasterCast provides a non-flammable clear art coating resin that won't shrink, distort or yellow over time. Solvent and odor free.