Varnishing Paintings

This is a good topic for both artist and collector.  Artists must decide if, when and how to varnish.  And as a collector, you should be aware of how the painting you purchased was or wasn't varnished.  I recently spoke with the folks at Gamblin about varnishing (I use their Gamvar varnish) and with their permission, have included a link to their varnishing studio notes here.

I have multiple reasons for varnishing.  First, it is an aesthetic decision.  As I'm painting, all values and colors relate to each other when wet.  As they dry, they change color slightly and look less saturated.  Varnishing will unify the gloss of the surface and saturate color.  Since my original intent was the values and color I saw when wet, I varnish in order to retain that look.  Varnishing can also protect against dirt and in Gamvar's case some UV light, though protection from UV light is at it's best when freshly mixed.

Gamblin's synthetic resin component system was developed by conservation scientists at the National Gallery.  Unlike natural damar resins, Gamvar won't yellow or darken.  It can be removed with a mild solvent such as mineral spirits, while damar varnish is harder to remove, endangering the top layers of paint, especially if glazes were used.  The component system allows for mixing when needed which makes the varnish the most effective.  I mix when I'm ready to varnish a group of paintings, date the mixture, and use it within one month.  I mix Cold Wax Medium into the varnish to create a more matte varnish, then apply two thin coats to each painting, waiting 24 hours to dry in between.  I've started to write the date I varnished the painting on the back of each painting so the collector who buys the piece will know when and what was used.

Bottom line, as a collector, you should know what was used on the painting you purchased, if anything.  Artists should research this for themselves and decide what's best for their work.