Probing the chemistry of CdS paints in The Scream by in situ noninvasive spectroscopies and synchrotron radiation x-ray techniques

Letizia Monico (1) , Laura Cartechini (1) , Francesca Rosi (1) , Annalisa Chieli (1) , Chiara Grazia (1) , Steven de Meyer (2) , Gert Nuyts (2) , Frederik Vanmeert (2) , Koen Janssens (3) , Marine Cotte (4, 5) , Wout de Nolf (4) , Gerald Falkenberg (6) , Irina Crina Anca Sandu , Eva Storevik Tveit , Jennifer Mass , Renato Pereira de Freitas (7) , Aldo Romani (1) , Costanza Miliani (1)

1 UNIPG - Università degli Studi di Perugia = University of Perugia
2 UA - University of Antwerp
3 RMA - Rijksmuseum Amsterdam
4 ESRF - European Synchrotron Radiation Facility [Grenoble]
5 LAMS - Laboratoire d'Archéologie Moléculaire et Structurale
6 DESY - Deutsches Elektronen-Synchrotron [Hamburg]
7 Federal Institute of Rio de Janeiro (IFRJ)

The degradation of cadmium sulfide (CdS)-based oil paints is a phenomenon potentially threatening the iconic painting The Scream (ca. 1910) by Edvard Munch (Munch Museum, Oslo) that is still poorly understood. Here, we provide evidence for the presence of cadmium sulfate and sulfites as alteration products of the original CdS-based paint and explore the external circumstances and internal factors causing this transformation. Macroscale in situ noninvasive spectroscopy studies of the painting in combination with synchrotron-radiation x-ray microspectroscopy investigations of a microsample and artificially aged mock-ups show that moisture and mobile chlorine compounds are key factors for promoting the oxidation of CdS, while light (photodegradation) plays a less important role. Furthermore, under exposure to humidity, parallel/secondary reactions involving dissolution, migration through the paint, and recrystallization of water-soluble phases of the paint are associated with the formation of cadmium sulfates.

Mots clés: BONHEUR-DE-VIVRE; ABSORPTION NEAR-EDGE; CADMIUM YELLOW; ULTRAMARINE BLUE; DEGRADATION; PIGMENT; FLUORESCENCE; DIFFRACTION; BEAMLINE; SULFIDE

Domaines: Chimie

Letizia Monico, Laura Cartechini, Francesca Rosi, Annalisa Chieli, Chiara Grazia, et al.. Probing the chemistry of CdS paints in The Scream by in situ noninvasive spectroscopies and synchrotron radiation x-ray techniques. Science Advances , 2020, 6 (20), pp.eaay3514-1-eaay3514-12. ⟨10.1126/sciadv.aay3514⟩. ⟨hal-03727371⟩