Encaustics (Beeswax) Encaustics is a classic art developed by the ancient Greeks. Beeswax is the main ingredient of encaustic medium and damar resin (pine tree sap) is added to increase the hardness of the wax. The pigmented medium, brushes, and painting surface are heated to keep the wax fluid while working. The final painting has unique depth and luminescence only found in encaustic work.