Encaustic paintings are built up in layers of pigment wax, which is melted and applied to the surface, then heated so that each layer is bonded to the previous layer. Encaustic is the most versatile, the most durable, and arguably the most beautiful of any artist's media. The exquisite surface qualities encompass delicately thin glazes and super-thick encrusted impastos. Because the wax is semi- transparent, light and colors from the lower layers can be seen through the upper layers. The wax can be cast, carved, scribed into, and impregnated with collage materials. The paint cools as soon as it is applied as if it had no "drying time." Yet it can be reheated and reworked later, as if it had infinite "drying time." Unless the finished work is heated above 140 degrees F, the medium is perfectly stable. Encaustic was used 2,000 years ago in Greco-Roman Egypt, where some of the tomb portraits are as fresh and glowing as when they were first created.