Q: What is the best final coating to put on oil paintings?
A: Varnish. Some varnishes are made with a synthetic
resin base, mastic gum, or damar gum. This final layer gives the
surface a consistent appearance while protecting it from dust and
atmospheric impurities.
A good varnish will be able to contract and expand in response to
atmospheric conditions. Brittle lacquers, for instance, do not make
good picture varnishes. A good varnish should also be transparent and
colorless. Damar is distinctly yellow, and gets darker with age.
Look for Sennelier's new final painting varnishes this fall; they
will be available in a variety of final finishes, including matte,
satin, and glossy. Sennelier will also offer varnishes for works in
progress that are designed to correct sinkage and allow for restarting.
--by Camille LaPointe-Lyons