"ENCAUSTIC" means to Burn In.
This is the process of applying molten wax colours to a surface for the creation of images and decoration. It is believed that this form of artwork was started some three thousand years ago and has its roots in ancient Egypt. Portraits of the dead, using Encaustic Art methods, were created and bound to the head area of Mummy Wrappings.
No one can say for sure what the original components of the wax paints were since there are a number of formulae and a number of techniques that have been discovered in the creation of the original Roman/Egyptian wax portraits that have been uncovered. However the wax colours seem to have been applied with some haste, which would make sense if the wax was molten and liable to cool on the implements.
In the days of the Pharaohs, there were two basic methods of carrying out this art form, these were the Hot Wax Method and the Cold Wax Method.
The Hot Wax Method:
This is how we might appreciate Encaustic in its true sense - using heat as the solvent for beeswax based pigmented wax paints. It is generally agreed that there were three types of tool used in the working of the wax.
Cauntarium - probably a type of metal palette knife that would be used heated to blend the different wax colours.
Cestrum - A small needle shaped item with a point that may have been used to draw in the hot or cold wax, but was probably used more in the molten wax.
Pencillium - These are brushes that are used to apply most of the wax colours in the backgrounds and portraits.
It appears that thin wooden panels were the favourite choice to paint on with molten wax, although linen was sometimes used, remembering also, that these portraits were designed to be bound over the head area of the Mummy's wrappings, so they were therefore, required to be pliable to a certain degree. Thin wood and linen would serve this purpose.
The wax would be heated by some means and once moulton the pigments of colour would have been blended to a volume of wax and then applied to the wood or linen surface using a brush. For finer detail a brush would have been dipped into the moulton wax and applied to the material in the normal paining style.
When viewing the portraits created in this manner, it seems that the main body of paint was applied using brushes and then later on, tooled with the hot instruments named above, to form a greater blending and variety of thickness.
The Cold Wax Method:
Apparently two men of ancient history, Pliny and Dioscorides, gave very similar recipes for Punic Wax. They told of a process where beeswax is boiled in sea salt water then strained through cheesecloth to remove impurities. This cleansing was carried out several times after which they decreed that the wax should be left in the Sun or Moonlight for several days to achieve a better bleaching of the wax. After this process was completed the wax needed to be saponified, (Made Soap Like), by adding Sodium Hydrogen Carbonate (Sodium Bicarbonate). This was mixed together and then later drained, again through the cheese cloth, then rinsed in lukewarm water and finally air dried. It would then be tempered for painting by mixing it with other ingredients:
Oil To improve and help keep it fluid (probably Linseed)
Egg Yolk To improve adhesion to the support and add resilience to the wax making it slightly harder.