Application of Synchrotron Radiation-Based Micro-Analysis on Cadmium Yellows in Pablo Picasso's Femme

Abstract

The cultural heritage community is increasingly exploring synchrotron radiation (SR) based techniques for the study of art and archaeological objects. When considering heterogeneous and complex micro-samples, such as those from paintings, the combination of different SR X-ray techniques is often exploited to overcome the intrinsic limitations and sensitivity of the single technique. Less frequently, SR X-ray analyses are combined with SR micro-photoluminescence or micro-Fourier Transform Infrared spectroscopy, which provide complementary information on the molecular composition, offering a unique integrated analysis approach. Although the spatial correlation between the maps obtained with different techniques is not straightforward due to the different volumes probed by each method, the combination of the information provides a greater understanding and insight into the paint chemistry. In this work, we discuss the advantages and disadvantages of the combination of X-ray techniques and SR-based photoluminescence through the study of two paint micro-samples taken from Pablo Picasso's Femme (1907). The painting contains two cadmium yellow paints (based on CdS): one relatively intact and one visibly degraded. SR micro-analyses demonstrated that the two Cd-yellow paints differ in terms of structure, chemical composition, and photoluminescence properties. In particular, on the basis of the combination of different SR measurements, we hypothesize that the degraded yellow is based on nanocrystalline CdS with high presence of Cd(OH)Cl. These two characteristics have enhanced the reactivity of the paint and strongly influenced its stability.

A study of Cadmium Yellow paints from Joan Miró’s paintings and studio materials preserved at the Fundació Miró Mallorca

“…4). In the recent past this peculiar and intense emission has been observed also in other paintings with degraded CdY paints [15,52] and its origin has been related with reactive cadmium yellow paints, possibly made starting from nanocrystalline or poorly crystalline CdS pigments [16,17].…”

“…During this study, the degraded paints were identi ed as cadmium yellow (CdY). The deterioration of CdY based paints has been reported in paintings including The Scream by Edvard Munch [7,8], as well as in other artworks by Van Gogh [9][10][11], Matisse [11][12][13][14], James Ensor [15] and Picasso [16,17]. Through these studies and further analyses on model paints [18], the degradation pathway of CdY (from the yellow CdS to the white CdSO 4 /CdSO 4 •H 2 O) was established and the possible factors that have a key role in CdS paints degradation were identi ed.…”

A Combined Experimental and Computational Approach to Understanding CdS Pigment Oxidation in a Renowned Early 20th Century Painting

“…The nature of the alteration of the flaking impasto paint in The Scream (ca. 1910) as well as that of hex-CdS paint in other artworks was revealed to be an oxidation process; various amounts of CdSO 4 , other sulfates, and sulfite species have been encountered in several investigations, ,− which can be interpreted as oxidation products. In addition, both in The Scream (ca.…”

“…Cadmium sulfide-based yellows (CdS/Cd 1– x Zn x S), which are present in a number of artworks by well-known artists including Henri Matisse, − Vincent van Gogh, James Ensor, Pablo Picasso, and Edvard Munch, have been documented to suffer from discoloration, flaking, and chalking of the paint films. In these cases, whitish compounds, such as cadmium sulfates (CdSO 4 /CdSO 4 · n H 2 O), − cadmium oxalate (CdC 2 O 4 ), − and cadmium carbonate (CdCO 3 ), − have been identified and tentatively proposed as either (photo)­degradation products of the original cadmium yellow paint or residues of the synthesis process of CdS.…”

Non-resonant inelastic X-ray scattering for discrimination of pigments

“…7 These methods were also coupled to understand the reactivity of crystal defects in cadmium-based (CdS) nanoparticles a Universite ´Paris-Saclay, ENS Paris-Saclay, CNRS, Photophysique et Photochimie in yellows from Pablo Picasso's Femme (1907) by correlating elemental and structural distributions with optical emissions to identify degradation mechanisms. 13 In these studies, analysis was performed on prepared samples from the painting, usually in the form of cross-sections. Alternatively, some studies only explored the sample surface due to the limited depth of information constrained by the appropriate edge energy.…”