As painters, you might know that other painters do it. As collectors, you might know that some of your artists do it. So…what is varnishing and why is it important?
Picture varnishes serve two important functions – first, a varnish layer protects oil paintings from environmental dirt and dust. The second reason is based on aesthetics – artists varnish because they like the way varnishes increase the sense of depth in oil paintings, or to achieve a uniform surface quality on their finished works. This article briefly discusses both of these concerns, for the artist and the collector.
Protecting Our Paintings
It is generally recommend that finished paintings are varnished, unless the artist truly dislikes the look. Unvarnished paintings are vulnerable to aging in ways that varnished paintings are not. As an artist myself, I know that once a painting leaves my studio, I give up control over how and where the painting is hung and how it is cared for. Very few, if any, private collectors keep their homes at the uncontaminated levels and controlled climates that museums do.
There are two important criteria that a quality picture varnish must have – first, the varnish must be water-clear to not change or alter the color scheme of the painting below. Second, the varnish must be easily removable in the future. The top-most layer of any painting will ultimately take on a layer of dust and dirt. Varnishes provide a non-porous layer which will prevent the dust and dirt from being imbedded in the more porous paint layers below (see diagram below).
If and when the painting needs to be cleaned, the varnish layer can be easily taken off of the painting, along with the dust and dirt that has accumulated on top. In this way, a varnish should be thought of as a discrete, “sacrificial” layer to the rest of the painting below.
Enhancing the Painted Image
It is not uncommon for paint layers to dry to different surface qualities. Some pigments used in oil colors require more oil and dry with more gloss, other pigments require less oil and dry matte. Varnishing is an excellent way of unifying the surface quality of paint layers. But what type of surface is right for the painting? High gloss? Dead matte? Something in between? Finding the appropriate surface quality is a very personal choice. Gloss surfaces beautifully saturate dry paint layers and increase the sense of depth in paintings. Matte surfaces give paint layers a very direct appearance, but can lighten the darkest values of a painting. Historically, representational painters preferred a gloss surface because of the increased sense of depth. Abstract painters adopted matte surfaces to enhance the physicality of paint layers. This, of course, is an over-generalization. What’s most important is that painters find the right surface quality for their work.
The other aspect of this is how the environment affects the viewing of the work once the painting is installed. Paintings that have a gloss surface can be difficult to see if they are not lit properly. This can take away from the painted image to the point of being distracting. Fortunately, the surface quality of the final varnish layer can be easily modified to accommodate both the painter’s aesthetics and the painting’s environment.
Traditional dammar varnish and other natural resins make a durable top layer but they do yellow and darken over time becoming increasingly difficult for conservators to remove when they clean paintings. In the mid-20th century, acrylic resin varnishes were adopted because of their stability of color. However, these varnishes changed the look of paintings, so many conservators went back to the use of dammar, along with its tendency to yellow with age.
In the early 1990’s, Robert Gamblin collaborated with Rene de la Rie at the National Gallery in Washington, DC, to bring a contemporary varnish to the studio painter. The research that came out of the National Gallery identified one of the most stable resins to be used as a picture varnish. This resin not only beautifully saturates dry paint layers, but is also formulated into a varnish with a very mild solvent. Equally as important, this varnish can be removed with a mild solvent. Gamvar Picture Varnish has now been available to painters for two decades.
To Varnish, or Not to Varnish
Similar to finding the appropriate frame for a painting, applying a varnish is an excellent way of putting a finishing touch on a work of original art. Not only does a final varnish coat unify and saturate color, but it plays an invaluable role in protecting your deeply-valued painting, whether you are the creator or collector.
In short, Varnish!
Product Manager, Gamblin Artists Colors
Recent Studies on Modern Paints: http://www.gamblincolors.com/newsletters/recent_studies_on_modern_paints.html