Q. What can you tell me about varnishes for watercolor paintings?
A. For many years, watercolor paintings didnt bring the same price as oil paintings by the same artist. And so some painters resorted to varnishing their watercolors to make them look like oil paintings.
But natural resin varnishes such as mastic and damar have pronounced yellowing as they age. Removal of the varnish is virtually impossible. The varnish also darkens watercolors, since it saturates the paint and paper. (Some watercolorists, though, like this effect. You can achieve the same results by brushing gum arabic onto the area, as Winslow Homer and others did.)
Today there are synthetic varnishes designed for watercolors. But while some of them wont yellow, they do saturate the colors and arent easily removable. The vast majority of watercolors are exhibited under glass and therefore dont need varnish to keep grime off the surface. I still recommend this as the best course.
Jerry McClish, of Bradenton, Florida, is a contributing editor to The Artists Magazine.