There is a lot of interest online in the prospect of varnishing oil paintings sooner than has been traditionally recommended.
When I was in art school, and ever since, I’ve been told it’s necessary to wait six to nine months to varnish an oil painting. For the most part, this is still true. However, after some research into the matter, there appears to be an exception to that rule in the form of a certain varnish formulation.
Gamvar by Gamblin is promoted as different from other varnishes. According to the manufacturer, it permits varnishing oil paintings sooner than others, typically one to two months or even less depending on the thickness of the paint.
Gamblin describes a “thumbnail test” to determine if the paint is thoroughly touch dry. Press on the paint in the thickest area with your thumbnail and if it does not make an indentation, it’s dry enough.
So what makes it different?
Varnishes contain a solvent as well as resin. They are meant to be removeable with solvents so the painting can be revarnished if the surface becomes dirty or damaged.
One of the problems with varnishing too soon is the tendency of the solvent in the varnish to partially dissolve the oil layer if not completely dry. This would allow the varnish merge with the paint film in a way that is not removable without damaging the paint.
According to Gamblin’s online information, Gamsol, the solvent in Gamvar, is milder than other solvents. Because of that, it’s less likely to interfere with the paint film, allowing for earlier application.
See their description here, under the link for “When can I varnish?”
This post was not in any way sponsored by Gamblin. It’s just the result of what I’ve found in answer to this question, though I’ve relied on the information on their website in understanding the issue.
Gamblin worked in cooperation with conservators at the National Gallery of Art in the development of Gamvar, so I trust their evaluation of its capabilities. Bear in mind, though, that the reliability of this method has not been proven over periods beyond 25 years or so. If you want to be careful and conservative about it, wait six months as tradition dictates.
I’ve used Gamvar before, simply because it had a good reputation. I have not yet used it on the shorter timeline, but I’ll be trying that with my next varnished oil painting.
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