Encaustic is a painting medium using a wax and resin based paint. It is valued for its rich luminous surface and its versatility for use with other artists' mediums. Encaustic paint is typically applied to a rigid absorbant surface, often in multiple layers. The wax based paint must be melted to become fused to the rigid base, and each subsequent layer of paint must be fused to the previous layer. This process of melting and fusing is what the word encaustic refers to - it comes from Greek and means “to burn in”. Typically, the wax in the paint is beeswax and the resin is Damar, which is a sap from a tree in the East Indies. The Damar resin raises the melting temperature and gives the wax paint extra hardness and shine. The final paint surface can be polished to a gloss.
The use of encaustic paint dates back to the 5th century B.C.E. The Greeks used coatings of wax and resin to waterproof ships and added pigment for decoration. The best known encaustic works are the Fayum funeral portraits, which were found in tombs along the Nile. They were painted in the 1st and 2nd century A.D. by Greek painters in Egypt. A portrait of the deceased was painted on wood and placed over the mummy as a memorial. Many of these pieces have survived and their colors are still vibrant. Encaustic was also used for murals, on statuary and on architectural stonework. After the 5th century the medium was rarely used. It was replaced by tempera and oil, which were less cumbersome. In this century, with the availability of portable electric heating implements, it has enjoyed a resurgence, and is being used with an amazing amount of variation and experimentation.
For my own artwork I use filtered beeswax and I make most of my own paints. The encaustic paint is kept liquid in containers sitting on a hot plate set to about 200 degrees. For color, I add dry pigments to the wax. Different types of pigments allow for varying levels of transparency and opacity. The paint is applied with brushes that are kept warm on the hot plate. Each new layer of wax is carefully melted with a propane torch, electric iron or heat gun to fuse it to the layer below. The wax hardens immediately and can be carved, shaped or incised and engraved with tools. Multiple layers are built up and can be selectively scraped away to reveal what's below. Areas can be remelted and reworked. Collage elements can be added and embedded. I frequently include paper, alone or with drawing, using pencil, colored pencil, and ink and other mediums. For a rigid substrate, I typically paint on high quality birch plywood.
On an encaustic painting, for several months after the wax was last melted, it subtly and slowly cures and hardens. During this period the surface may become slightly cloudy. This is called bloom, and it's more visible on darker colors. It's not a defect. The surface may be gently polished with a soft clean cloth to dispel the bloom and restore a lustrous shine without harming the artwork.
Because wax is impervious to moisture and air, it doesn't easily deteriorate and doesn't need to be protected with a varnish or glass. It will not yellow or darken with age. Although, like most fine art, colors are still susceptible to fading from UV radiation and it should be kept out of direct sunlight. Temperatures need to get much hotter than your home to damage the wax - typically above 170 degrees. I do try to avoid shipping in extremely hot or cold weather when artwork may be more prone to damage.