Evidence for Degradation of the Chrome Yellows in Van Gogh's Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron-Radiation-Based X-ray Techniques

Letizia Monico; Koen Janssens; Ella Hendriks; Frederik Vanmeert; Geert Van der Snickt; Marine Cotte; Gerald Falkenberg; Brunetto Giovanni Brunetti; Costanza Miliani

doi:10.1002/anie.201505840

Evidence for Degradation of the Chrome Yellows in Van Gogh's Sunflowers: A Study Using Noninvasive In Situ Methods and Synchrotron-Radiation-Based X-ray Techniques

Angew Chem Int Ed Engl. 2015 Nov 16;54(47):13923-7. doi: 10.1002/anie.201505840. Epub 2015 Oct 20.

Authors

Affiliations

¹ CNR-ISTM and SMAArt Centre, Department of Chemistry, Biology and Biotechnologies, University of Perugia, via Elce di Sotto 8, 06123 Perugia (Italy). letizia.monico@istm.cnr.it.
² Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium). letizia.monico@istm.cnr.it.
³ Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium).
⁴ Conservation Department, Van Gogh Museum, Paulus Potterstraat 7, 1070 AJ Amsterdam (The Netherlands).
⁵ ESRF, Avenue des Martyrs 71, 38000 Grenoble (France).
⁶ LAMS, CNRS UMR 8220, Sorbonne Universités, UPMC Univ Paris 06, place Jussieu 4, 75005 Paris (France).
⁷ DESY, Notkestrasse 85, 22607 Hamburg (Germany).
⁸ CNR-ISTM and SMAArt Centre, Department of Chemistry, Biology and Biotechnologies, University of Perugia, via Elce di Sotto 8, 06123 Perugia (Italy).

PMID: 26482035
DOI: 10.1002/anie.201505840

Abstract

This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-x Sx O4 (x≈0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr(III) compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future.

Keywords: X-ray absorption spectroscopy; dyes/pigments; lead chromate; photoreduction; vibrational spectroscopy.

Publication types

Research Support, Non-U.S. Gov't