We brought this lovely landscape, Waterloo Bridge by British artist John Constable (1776-1837), into the conservation lab to be examined for the British catalog project. Not conserved for more than 60 years, the painting’s varnish is now noticeably yellow. The cool blue sky over the Thames River in 1820s London is dulled, and the water has lost its sparkle. 

After thoroughly examining the painting, we performed some cleaning tests. The clean spots, as you can see in the photo, demonstrate that removing the varnish will transform the scene.

We swabbed with a number of different solvent mixtures to find one that would dissolve the varnish safely and slowly … but not too slowly. A solution that is very slow means the surface needs to be swabbed multiple times, increasing the mechanical action on the surface. So, paintings conservators try to find an efficient mix of solvents to dissolve the varnish slowly, without affecting the paint surface, but also without requiring numerous swabs.

Solvent mixture decided, varnish removal is now underway. The varnish we apply after cleaning is more stable and will not yellow over time.

The whole conservation treatment should not take very long. Look for the painting to be back on view in Gallery 209 within the next two or three weeks.