Cleaning and varnish and overpaint removal
The removal of layers of dirt (including smoke damage, accumulated atmospheric pollution, nicotine, soot etc.) from paintings is carried out following careful tests to ensure that no damage is done to the underlying layers of paint, glazes and varnishes.
In some cases this may be all that is required to bring the image back to an acceptable level of visibility.
The removal of layers of often dull and darkened varnish is considered and carried out even more carefully, given the potential for there to be artists glazes or tinted varnishes present. It is also sometimes the case that artists’ signatures are painted on top of a varnish. Replacing old varnish with new, in contemporary restoration practice, means using modern, conservation grade resins which do not tend to yellow and remain reversible.
The removal of layers of overpaint (previous restoration) can be done following tests and examination. Some overpaint may look unsightly but conceal large losses in the original paint whilst some may have an acceptable appearance. Old retouching carried out in oil paints will almost always have darkened over time. These are some of the factors to consider and why removing such layers is undertaken on a case by case basis.
Varnish and/or overpaint removal is considered after close inspection (often involving UV light examination) and tests. In complex cases this may involve more technical photographic analysis and some laboratory work. The emphasis in all cases is to avoid ‘over cleaning’, (the removal of artists original material).