Have you ever wondered if a painting you own is less vibrant than it should be? Does the entire surface appear yellow? If a layer of dirt, grime, or old varnish covers the surface, then you may be viewing your painting through a discolored film. Perhaps what you are looking at is obscured and the painting is more beautiful than you ever imagined. In obvious cases, a painting may be so dark that the subject is barely discernable and a cleaning is clearly needed. In other instances, the discoloration may be less apparent, but still obscure the true colors painted by the artist. "We have seen many paintings where the sky appears more green than blue due to a yellowed varnish," explains Bill Santel, Lowy’s chief conservator.
An experienced conservator can run tests to determine whether your painting can be safely cleaned and you may be in for a very pleasant surprise. But how do you know when it is time to bring your painting to a conservator and whether it should be cleaned?
It would be wise to have your painting evaluated if it has been in a private collection for many years and not examined by a conservator or, if based on your knowledge of the work of a particular artist, the colors appear dull or discolored.
As a rule, the natural resin varnishes used up until the 1950’s, when synthetic varnishes were introduced, yellow over time. But even synthetic varnishes can discolor depending on application and environmental factors. Dirt and grime can accumulate on the surface subject to the conditions in which a painting is kept. An artwork that has hung over a well-used fireplace for many years may darken excessively, and a contemporary painting that is unvarnished can be at an even greater risk for permanent damage because there is no protective layer over the surface.
Not all paintings can be cleaned. Depending on the techniques and mediums used, the grime could be embedded in the paint or the varnish could be cross-linked with the original paint layer. Glazes on the surface of a painting can be integral to an artist’s technique and if these glazes discolor over time, then removing them may change the intended appearance of the painting and be unadvisable. For this reason, careful solvent and detergent tests should be conducted before any cleaning is done. Contemporary paintings pose a whole new range of cleaning issues due to the unconventional materials used in them. It is recommended to turn to a conservator who is experienced in cleaning the type of painting in question or, if possible, in cleaning actual works by the artist who painted the piece you wish to clean.
Never conduct tests on a painting yourself. Solvents can damage a sensitive medium if not handled properly and even detergents can discolor or cause “blanching,” a white haze, to form in some instances.
This article was reproduced with permission of Lowy. If you have questions about conservation please visit their website by clicking here.