When should a painting be varnished?

Varnishes have been used- or not used- by artists for centuries to create visual effect and provide surface protection. As conservators, we are frequently asked whether a painting should be varnished when it is cleaned or restored. To do this, one needs to evaluate the painting's condition, understand the artist's original intent, and be familiar with the history of varnish.

A brief history of varnish: In general, most Western paintings prior to the late 19th century had a protective surface coating of some kind. "But then," explains John Neuhoff, one of Lowy's painting conservators, "some of the Impressionists decided they preferred the look of their paintings unvarnished. Couple that with the fact that for a variety of aesthetic reasons many 20th century artists also chose to omit the varnish, and you can see why the decision to varnish a work is not easily made."

A case-by case analysis: The conservator must thoroughly analyze the painting to learn the chemical composition of the existing varnish and determine if it can be removed safely. He should also ascertain whether (and to what extent) the existing varnish is discolored and see if the painting itself has structural or cosmetic problems that will require removal. The intent of the artist and the general "type" of painting must also be considered. (As a rule, works such as paintings with areas of raw canvas, collage, newsprint or gloss/matte paint combinations should not be varnished.) Reversibility is a concern when varnishing works in acrylic. And of course, the individual artist's tendency to use varnish should be researched. Armed with this information, the conservator and the client will jointly decide if a new varnish should be applied. "If a layer of varnish will enhance- and not alter- the appearance of the painting, it is usually recommended," Neuhoff asserts.

Modern varnishing techniques: When a previously varnished painting has been cleaned, it is generally recommended that it be re-varnished with a tin layer of synthetic resin. (Synthetic resins are most desirable because they are reversible and discolor very minimally, even over long periods of time.) "We often wonder," muses Neuhoff, "if the Impressionists would have felt more favorably about varnish if they had the products we have today." And after all aesthetic concerns are addressed, there is another issue to consider: safety. "Remember the case of Picasso's 'Guernica?' It was sprayed with red paint by a vandal, but thanks to a coating of a varnish called Acryloid B-72, it was easily restored."

What should I look for when choosing glass for my work on paper?
David Frye, a manager of Lowy's Fitting Department, has a good understanding of this complex subject. "Protection from ultraviolet light is a very important feature, though the UV film can sometimes add a slight tint. And if the composition has large dark areas, reflection control glass might be desirable." Frye cautions that reflection control is different from the more common (and less expensive) non-glare glass, which is etched and does not provide absolute clarity.

Think glass is the obvious choice? Think again. Since plexiglass weighs less than glass- and is shatterproof- it can be the wisest choice for works that are large and/or handled often, and that don't contain any loose mediums. "But on the other hand," says Frye with mock exasperation, "plexi scratches easily, so some might say it is the worst choice for a work that is frequently moved." Even more importantly, the high electrostatic tension of plexiglass can draw loose particles from a charcoal or pastel off the surface and onto the plastic. "As a result," David continues, "elements of the artwork can be lost."

"Amiran TN by Schott is the Rolls Royce of glass," he asserts, "but it doesn't come cheap." The product, which is actually a composite of two sheets of low iron glass is shatterproof, virtually colorless, offers UV protection, glare resistance, and very low electrostatic activity. "Ironically, Amiran TN came to fame during the Vermeer exhibition at the National Gallery because people didn't notice it," laughs Frye. So what's the catch? The cost can be four times higher than other high quality glazing products, and Amiran is often difficult to obtain due to persistently high demand.

It doesn't take a crystal ball to decide how to glaze an artwork- it just takes knowledge. So to help you sort it all out, we've made a chart that shows the attributes of several leading products. Of course, when you have work on paper framed at Lowy, we will help you with your glazing selection.