Abstract
The discoloration rate of chrome yellow (CY), a class of synthetic inorganic pigments (PbCr1−xSxO4) frequently used by Van Gogh and his contemporaries, strongly depends on its sulfate content and on its crystalline structure (either monoclinic or orthorhombic). Macroscopic X-Ray powder diffraction imaging of selected areas on Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam) revealed the presence of two subtypes of CY: the light-fast monoclinic PbCrO4 (LF-CY) and the light-sensitive monoclinic PbCr1−xSxO4 (x≈0.5; LS-CY). The latter was encountered in large parts of the painting (e.g., in the pale-yellow background and the bright-yellow petals, but also in the green stems and flower hearts), thus indicating their higher risk for past or future darkening. Overall, it is present in more than 50 % of the CY regions. Preferred orientation of LS-CY allows observation of a significant ordering of the elongated crystallites along the direction of Van Gogh's brush strokes.
Original language | English |
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Pages (from-to) | 7418-7422 |
Journal | Angewandte Chemie - International Edition |
Volume | 57 |
Issue number | 25 (Special Issue) |
DOIs | |
Publication status | Published - 2018 |
Bibliographical note
Special Issue: Heritage Science Plus Analytical Chemistry, Spectroscopy, and BioanalysisKeywords
- analytical methods
- dyes/pigments
- imaging
- lead
- X-ray diffraction