Surface Preparations
Supports
Pigment Sticks can be used on any support proper for oil or encaustic
painting. This includes stretched canvas, rigid board, or paper.
Sizing
As in oil painting, all canvas and paper surfaces should be sized. To
size, use one or two coats of the following in dilute solution: 1) any alcohol-based
varnish, such as shellac, 2) rabbit-skin glue, or 3) acrylic medium or acrylic gesso.
When sizing paper, with acrylic medium, dilute the acrylic with water
and spray several thin coats, drying between coats. This will help prevent the water from
curling the paper and also keep the texture of the paper from being covered with a heavy
plastic coating. Portable pressurized sprayers are good for laying on the size in a fine
mist.
Grounds
The preferred ground for Pigment Sticks, as for any oil paint, is an
oil ground of titanium or lead white. Acrylic gesso is commonly used today and is probably
OK, but it is more flexible than oil paint, and the long term adhesion of an oil film to
the more elastic acrylic film is not yet proved. Paper that has been sized does not
require a ground.
Varnishing
When thoroughly dry, Pigment Sticks can be varnished. However, a number
of cautions should be taken into consideration about the varnishing of any wax-bearing
paint. The solvent in a varnish (such as turpentine or mineral spirits) will partially
dissolve the wax, "reactivating" the surface.
While a careful application of the varnish will not significantly
disturb the paint, the removal of the varnish coat in any future restoration work would
require a much heavier solvent use, which could endanger the paint film. The textures
created by an oil stick add further complications to the removal.
Retouch varnish, on the other hand, is applied for the purpose of
evening out patchy finishes and is not intended to be removed. If applied carefully with a
sable brush, it should not cause any harm to the paint film.