This beautiful landscape by Impressionist Alfred Sisley was recently being cleaned of its varnish by our paintings conservator.  The varnish had become slightly yellow, as natural resin varnishes do over time as a result of light exposure. 

These days conservators tend to use synthetic resin varnishes that do not oxidize, or turn yellow.  And in both the synthetic and the natural resin varnishes that conservators make into solution, an additive to inhibit oxidation is part of the recipe.

In the case of the Sisley, the yellowing had a particularly strong visual effect on the picture.  That’s because the overall tone of the landscape is a cool violet-tinged hue.  And yellow, being violet’s complementary color, will always dull it down.  The varnish removal allows the painting to show its true colors.  A similar effect was visible when we cleaned CAM’s Monet a few years ago.

Moret at Sunset is headed out as a loan, but look for it to return to the galleries later in the year.