--2018-04-06--This post describes the drawbacks of damar varnish and modern alternatives, including specific products based on a synthetic resin called regalrez.
A note on applying varnishes:
I sometimes use my Paasche VL-5 airbrush to apply varnish, but most of the time I just brush it on with the painting lying flat. I once used a Preval spray kit to spray on my varnish of choice when I had to fly to Washington DC to varnish a portrait there, lacking my airbrush and compressor. The PreVal kit consists of a can of propellant and a jar in which to place whatever liquid you want to spray.
Damar is no longer the best varnish available, though it remains popular with painters who aren’t up to date on new materials. The drawbacks of damar varnish are that it grows more yellow with age, eventually turning brown, and becomes increasingly brittle, thus crack-prone, so it changes the appearance of the painting after 30-40 years, and has to be removed and replaced with new varnish.
There are now varnishes on the market that have the same desirable optical qualities as damar but do not yellow or embrittle, and these remain easily removable with milder solvents than are required to remove aged damar. These varnishes, developed by Rene De La Rie, conservation scientist at the National Gallery in Washington, are based on a synthetic resin called regalrez.
There are at least three companies who offer regalrez varnishes: Natural Pigments (Conservar,) Gamblin (Gamvar,) and Conservators Products Company (UVS Finishing Varnish.)
Varnishing Product Suggestions:
1. I’ve used UVS Finishing Varnish on many of my paintings, with good results every time.
2. Soluvar is an acrylic resin varnish that some museum conservators like, but it’s not my favorite because it will need to be removed and replaced in 40 years or so when the defects of acrylic resins begin to show up.
3. My experiences with Gamvar have all been positive.
I’m equally happy with Rublev Conservar, Gamblin Gamvar, and Conservators Products Company’s UVS Finishing Varnish. I have had no trouble with any of them.
MSA Acrylic Varnishes
There are also MSA acrylic varnishes available from Golden that some painters and conservators like. Those, too, are better than damar in most ways.
The WN gloss varnish is an acrylic MSA varnish that might be all right.
This is from a post in the archives from Sarah Sands, Production Research at Golden: “All synthetic resin varnishes, including our MSA and Archival Varnishes, are more porous then past natural resin ones and as such should allow oxygen to continue to penetrate. However, additional coatings of any type will slow this process down, and retouch varnishes, in general, are not well-liked by conservators. The issues are less about oxygen and curing than the fact that in young paint films the varnish will become more tightly integrated into the structure of the paint, making removal more difficult in the future without risking color lift. Also, exposure to solvents – even OMS – will invariably extract low molecular weight fractions from the paint film, including free fatty acids, and this can lessen the flexibility of the paint. While we know that people use our products in this way we do not recommend retouch varnishes in general unless the paint is at least hard-dry, are applied minimally, and are NOT painted on top of.”