Encaustic painting is a mixed media technique involving using melted beeswax and damar resin (a tree sap which serves as a hardener for the wax) which can be mixed with colored pigments. It is applied to a rigid, porous surface (such as a wood panel) in many thin layers, each fused to the layer underneath using a heat source (such as a propane torch). The term encaustic is derived from Greek, meaning to burn in.