Until recently most paintings were coated with varnish made from natural resins dissolved in appropriate solvents. These varnishes age by changing colour, transparency and/or elasticity. The aged varnish can be yellowed, crazed or milky in appearance. In either case, it alters the original appearance of the artwork and seriously compromises its overall aesthetic nature. Varnish removal requires a proficient knowledge of chemistry and conservation expertise. Not all areas within a painting are equally affected by a solvent, but those that are solvent-sensitive can become obliterated by a single stroke of a cleaner. Within the conservation trade this is known as skinning or overcleaning.
To varnish and re-varnishing
Traditionally, final, transparent coatings were applied for protection, but also for aesthetic reasons therefore their influence on a paintings’ appearance should not be underestimated. The presence of a varnish or a lack of it will considerably modify how we perceive a particular work of art; varnish will literally “filter” our vision. It does not only make a surface shiny (although there are mat varnishes as well) but it brings colors to life, accentuates the smallest of details and deepens the shadows in addition to other subtle changes.
The decision to varnish or not can reflect an aesthetic or ideological position of a particular artist or school and therefore should be given some thought. At In Restauro we have a sound art historical background and are able to advise whether a work of art should be varnished or not.
Certain techniques do not lend themselves to the required reversibility if varnished even with “conservation” varnishes and the original “look” may be lost forever. Paintings done in gouache or painted extremely thinly with diluted oil medium should not be varnished unless originally done so. Even a mat varnish saturates colours and gives them a certain sheen and depth which might be aesthetically wrong for the piece and/or period.
As often heard comment that a painting looks “dry” may be due to a particular technique and its historical placement should be carefully considered before (if at all!) a varnish is applied.
In Restauro 