Van Gogh Flowers Discolored by Varnish
A supposedly protective varnish applied to Van Gogh's famous painting "Flowers in a Blue Vase" after his death has turned some bright yellow flowers in the painting orange-gray. The degradation was discovered via x-ray analysis by scientists at the European Synchrotron Radiation Facility ESRF in Grenoble, France, and at Deutsches Elektronen-Synchrotron DESY in Hamburg, Germany.
Vincent Van Gogh (1853--1890) painted "Flowers in a Blue Vase" in 1887 in Paris, and in the early 20th century the painting was acquired by the Kroller-Moller Museum in the Netherlands. The master usually did not varnish his works, but this painting was later covered with a supposedly protective varnish, like many other Van Gogh paintings in the first half of the 20th century. "A conservation treatment in 2009 revealed an unusual grey opaque crust on parts of the painting with cadmium yellow paint," says paintings conservator Margje Leeu-western from the museum.
To identify what had happened, the team x-rayed two microscopic paint samples from the painting, revealing their chemical composition and internal structure. …