Encaustic, sometimes referred to as 'hot wax painting,' is an ancient technique used in Egyptian mummy portraits and Greek mural painting. The artist mixes pigments into the melted wax and then applies it with brushes and various tools. Then the surface is heated to fuse the layers of wax. Additionally, an encaustic can be polished to a final sheen, or reworked (through use of heat, again) as much as necessary until the artist is satisfied. The technique has become popular in the last thirty years and new ways of approaching the technique had emerged.