Using tree sap (amber) or, more commonly today, epoxy resin, artists can apply this chemical to their artworks while it is at a low viscosity. It can be mixed with various additives to supply different textures and pigments for different colors. Over a period of time determined by how much resin is applied, the resin can be mixed with a hardener and begin to solidify into an incredibly resilient plastic. For this reason, artists can not only paint objects but also cast them in resin, opening the door to a whole new world of creative opportunities.