Question asked 2018-09-27 15:20:04 ...
Most recent comment 2018-10-17 13:47:58
I am working on reconstructing a Fayum mummy portrait, and a few sources I've read have mentioned methods that might have been used to make the wax easier to paint with. There's a small section in "Ancient Egyptian Materials and Technology" about "punic wax" that suggests beeswax was possibly saponified to make it water soluble. Do you know if that theory is plausible or have you tried painting with punic wax?
Answers and Comments
This comes up every time Greek encaustic is mentioned. There is some debate as to just what Punic wax is. Some do think that it is a water soluble wax soap (the wax is heated in water containing either ammonium carbonate or sodium carbonate until it is saponified) Others believe that the Punic wax was simply a purified and bleached wax. It is theoretically possible that the wax was dissolved as above as these materials were certainly available at the time. They would result in a far less textured paint than regular encaustic (pigments in molten beeswax) Many of the highly textured portraits could probably only be made using heated wax given their surface. This is not to say that saponified wax was not used during the period and I have rerad where others feel that some of the effects seen in these early paintings would have tyo have been made with a saponified wax.
As to the use of saponified wax, it is no real pleasure to work with, at least in my opinion. That dissolved in ammonium carbonate is very granular. It would only be pleasant to work with if mixed with other ingredients like oils etc. The positive thing about Ammonium carbonate formulated soap is that its alkalinity and solubility in water diminishes after drying. Natural Pigments makes a formulated paint containing saponified wax and other ingredients. I believe that Ralph Mayer mentions a few recipes in his The Artists' Handbook
Wax saponified using sodium carbonate makes a soother vehicle but it retains its alkalinity (and probably its water sensitivity, although I have not tested this) even after drying and therefore there are a number of pigments that probably should not used (eg red lakes).
I will forward this to a few others to see if they have a different take on the subject.
Although Punic wax is claimed by
some to be one form of wax that was used in ancient encaustic
paintings, there is little proof to substantiate these claims. It may
be that some form of saponified wax was used by Greek and Greco-Roman
painters in Antiquity, but Punic wax may not be the form used, as its
description by Pliny in his book Natural History was in a section
about ship building and not art. In addition, the description of how
to make Punic wax is not clearly understood as some of the terms used
can apply to different substances used in its manufacture. Attempts
over the past centuries to make Punic wax into a painting medium have
largely been unsuccessful based on various alkalies put forth to
Saponified beeswax is prepared by
boiling beeswax with an alkali, which is the method some claim is
described by Pliny in his chapter on Punic wax. In this process,
long-chain fatty acids in beeswax form soaps. The water-soluble soaps
form an emulsion with the water-inmiscible components of beeswax—wax
esters and n-alkanes.
In my experiments, saponifying beeswax
did not result in a stable emulsion, unless other ingredients are
added, such as vegetable oils and resins. Producing stable
dispersions of beeswax is difficult whereas those formed with other
natural waxes, such as carnauba is much easier to achieve. There are
several methods of achieving a dispersion of beeswax in water that
avoid using other ingredients, such as vegetable oils, that
compromise the utility of beeswax as a paint binder.
Thanks so much George.
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