Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Analytical Chemistry

Van Gogh’s Red Is Turning White

Chemical analysis of paint sample taken from “Wheat Stack Under a Cloudy Sky” reveals the intricacies of degradation of pigment made from lead

by Bethany Halford
March 16, 2015 | A version of this story appeared in Volume 93, Issue 11

[+]Enlarge
Credit: Kröller-Müller Museum
“Wheat Stack under a Cloudy Sky” by Vincent van Gogh. Circle indicates where sample was taken.
A n image of “Wheat Stack Under a Cloudy Sky” by Vincent Van Gogh (1889). Circle indicates where sample was taken.
Credit: Kröller-Müller Museum
“Wheat Stack under a Cloudy Sky” by Vincent van Gogh. Circle indicates where sample was taken.

To achieve the brilliant reds in his paintings, Vincent van Gogh used paint made with Pb3O4, a red lead-based pigment. But this particular pigment appears to be slowly turning white, according to a report from Koen Janssens, Frederik Vanmeert, and Geert Van der Snickt of the University of Antwerp, in Belgium (Angew. Chem. Int. Ed. 2015, DOI: 10.1002/ange.201411691). The discoloration of lead-based pigmented paints is a well-known phenomenon. These paints, which have been used since antiquity, will darken or whiten, depending on the degradation chemistry of the pigment. What the Antwerp team found was a chemical “missing link” in this degradation process. The chemists used X-ray powder diffraction tomography to study a sample taken from van Gogh’s 1889 painting “Wheat Stack under a Cloudy Sky” (shown). In the space between the sample’s reddish-orange Pb3O4 core and the light blue PbCO3 layer that surrounds it, the chemists found plumbonacrite, 3PbCO3•Pb(OH)2•PbO. This is the first time this compound has been found in a painting dating before the mid-20th century, the authors note. The discovery, they say, sheds new light on how red lead degrades, and they propose a mechanism that involves carbon dioxide and light.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.