This site discusses theoretical processes of encaustic painting and my experiments to recreate the Early Roman techniques of painting. The site is all about experimentation to test theories of how the ancients may have painted.
So far as is known, the ancients had two methods for using wax as paint. The first method employed melted wax as a binder for pigments. Wax was heated to a liquid state, pigments were added and the resulting “paint” was applied to heated boards. The wax flowed like paint and remained fluid because the boards were hot. This was the hot wax technique.
The second method used watercolor (or some other as yet unknown media) under painting with an overlay of clear hot wax. When the under painting was finished, a clear wax overlay was applied and the painting became permanent. Both methods are called encaustic.
There are many unanswered questions concerning the methods of painting used by the ancients. Did they use gesso primers? If so, what was the composition? Was it casein? Was it cow hide glue? Was it some as yet undiscovered substance which science may some day reveal?
Did the ancients add oil or resin to their waxes? Resin, particularly Damar raises the melting point of wax and creates a hard surface. It would be subject to discoloration and cracking with age. Did the ancients use it? No one knows. I do not use it in my experiments. Other people do.
Oil added to wax makes wonderful soft crayons for pastel like work. So far, experimentation has shown that it does not work in the heated state because it separates from the wax just like oil and water.
What about saponification? I have not worked with saponification but other artists in the recent past have evolved a soluable wax medium that can be used on cold surfaces. (Take a look at Cuni Encaustics) It does work and it makes a lovely painting medium. There is no reason not to use it for modern work. Did the ancients saponify their waxes? The question is open for discussion and deduction of information from science and the scant references found in ancient texts.
Although we do not know whether or not the ancients may or may not have used it, the innovation of saponification came about from contemplating possibilities of how the ancients may have painted walls using wax and has yielded a new and beautiful painting medium. In a sense, this is the continuing evolution of a painting medium kept alive by scholars, archeologist, art historians and museum curators handing on to artists of today a legacy of questions, conjectures and theories upon which to build and further develop this very ancient painting medium.