An XPS study into sulphur speciation in blue and green ultramarine

Cato, Eleanor; Rossi, Antonella; Scherrer, Nadim; Ferreira, Ester S. B. (2018). An XPS study into sulphur speciation in blue and green ultramarine Journal of Cultural Heritage, 29, pp. 30-35. 10.1016/j.culher.2017.09.005

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A number of ultramarine paint samples were analysed by Raman spectroscopy and X-ray photoelectron spectroscopy to determine the binding energies of the S-3(.-)(blue) and S-2(.-)(yellow) radical anions responsible for the pigment colour. The two sulphur radicals (chromophores) have well assigned Raman signals, however, no previous XPS study has been able to observe both radicals in natural or synthesised blue ultramarine samples and assign binding energies. This study focused on the analysis of synthetic ultramarine samples, which have a higher chromophore concentration than natural pigments, and on the comparison of blue and green shades, as green pigments have a higher quantity of the yellow chromophore. XPS spectra from six blue and three green paints were processed and found to contain sulphide, sulphite, sulphate and two unassigned signals at 162.9 and 163.8 eV. The ratio of these two signals varied between blue and green samples. Raman spectra of the samples were measured and the ratio of the blue versus yellow signals at 549 cm(-1) and 580 cm(-1) calculated. Comparison of the Raman and XPS data sets found good agreement between signal ratios when the 162.9 eV XPS signal was assigned to the yellow and the 163.8 eV signal was assigned to the blue chromophore. (C) 2017 Elsevier Masson SAS. All rights reserved.

Item Type:	Journal Article (Original Article)
Division/Institute:	Bern Academy of the Arts Bern Academy of the Arts > Institute Materiality in Art and Culture Bern Academy of the Arts > HKB Teaching Bern Academy of the Arts > Institute Materiality in Art and Culture > Material analyses
Name:	Cato, Eleanor; Rossi, Antonella; Scherrer, Nadim0000-0002-6576-885X and Ferreira, Ester S. B.
Subjects:	C Auxiliary Sciences of History > C Auxiliary sciences of history (General) N Fine Arts > ND Painting
ISSN:	1296-2074
Language:	English
Submitter:	Nadim Scherrer
Date Deposited:	18 Dec 2019 09:07
Last Modified:	18 Dec 2020 13:28
Publisher DOI:	10.1016/j.culher.2017.09.005
Related URLs:	Publisher
Web of Science ID:	000424325800004
Additional Information:	Notes: Fv1mg Times Cited:0 Cited References Count:28 Date: 2018
Uncontrolled Keywords:	raman spectroscopy ultramarine chromophore x-ray photoelectron spectroscopy binding energy raman-spectroscopy sodalite pigments color
ARBOR DOI:	10.24451/arbor.8048
URI:	https://arbor.bfh.ch/id/eprint/8048