Basket of Pansies
Vincent van Gogh, 1886
Van Gogh often re-used his canvases, as in Basket of Pansies. He covered the earlier composition with a layer of lead and zinc white-based oil paint before executing the second painting. Such intermediate layers now often extrude through cracks in the paint layers and sometimes even the varnish on top.
The hypothesis that this is the result of zinc soap formation needs to be further investigated.
In the case of Basket of Pansies, the extruding paint appears wafer thin so that the painting is considered too fragile to travel. The painting was first varnished in 1932, contrary to the artist’s intention. The old varnish is now severely yellowed and brittle. But is it possible to remove the varnish without adversely affecting the extruding intermediate layer?