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Sunday, May 29, 2022

To Varnish...or Not to Varnish?

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Oil Painting Varnishes I Have Known

One of the questions that comes up in my workshops frequently from oil painters is, Should I varnish?  And this is quickly followed by, When?

Yes, you should varnish.  Varnishing serves to protect the paint layer from the environment and allows one to clean a painting without damaging the paint.  Where I live in New Mexico, we get a tremendous amount of dust from our springtime winds.  The dust, so fine, infiltrates through the smallest crack in doors and windows.  It settles on everything—even the vertical surface of a hung painting.  But a quick wipe with a damp cloth is enough to get the dust off, and I feel safe doing this because I know the varnish will protect the painting.  Also, if you're a messy cook and your kitchen regularly fills with grease and smoke when you fry up a hamburger, those tiny particles will travel a long way—all the way to that painting you have hung in the living room.  Over time, these particles will make a gummy mess, and your heirs and the art conservators they've hired will thank you for varnishing your painting.  Even if you live in a dust-free, grease-free and smoke-free place, the air still contains contaminants that the varnish will block.

But varnish does more.  Many pigments upon drying, especially the earth colors, will become duller and lighter in value.  Varnish will saturate the colors and deepen the values, making the painting look like it did when you applied that last brush stroke.  You worked so hard to get that look, why not keep it?  (If you don't want the “wet” look, choose a matte varnish rather than a glossy one; a matte varnish is also helpful in reducing glare on a dark painting.)

Interestingly, some of the French Impressionists and the Modernist painters didn't varnish their paintings.  They preferred the raw, matte finish of the dried oil paint.  But how a painting appears once dry is difficult for an artist to anticipate and work toward; instead, I prefer to achieve the look I want first and then to resurrect that look with varnish should the painting change.

And when to varnish?  If you're using a traditional varnish, one that contains tree resins such as damar, you need to wait six months or longer, until the painting is completely dry.  This is because a natural resin varnish seals the paint layer so solidly that oxygen can no longer reach it.  Because oil paint cures by oxidation, it will never thoroughly dry and will be subject to damage.  However, Gamblin makes a synthetic resin varnish—Gamvar—that allows the paint layer to continue to “breathe.”  You can apply Gamvar as soon as the painting is dry to the touch, often after just a few days.  I test the dryness by gently pressing a fingernail into the thickest spot of paint; if it doesn't leave a mark, I know the painting is dry enough for Gamvar. 

You can read more about varnishing in general on the Gamblin web site here:

and see a video on using Gamvar here:

By the way, if you're wondering what kind of brush to use for varnishing, Gamblin now offers the perfect brush, which you can read about here: