ToF–SIMS imaging of molecular-level alteration mechanisms in Le Bonheur de vivre by Henri Matisse

Abstract

Time-of-flight secondary ion mass spectrometry (ToF–SIMS) has recently been shown to be a valuable tool for cultural heritage studies, especially when used in conjunction with established analytical techniques in the field. The ability of ToF–SIMS to simultaneously image inorganic and organic species within a paint cross section at micrometer-level spatial resolution makes it a uniquely qualified analytical technique to aid in further understanding the processes of pigment and binder alteration, as well as pigment–binder interactions. In this study, ToF–SIMS was used to detect and image both molecular and elemental species related to CdS pigment and binding medium alteration on the painting Le Bonheur de vivre (1905–1906, The Barnes Foundation) by Henri Matisse. Three categories of inorganic and organic components were found throughout Le Bonheur de vivre and co-localized in cross-sectional samples using high spatial resolution ToF–SIMS analysis: (1) species relating to the preparation and photo-induced oxidation of CdS yellow pigments (2) varying amounts of long-chain fatty acids present in both the paint and primary ground layer and (3) specific amino acid fragments, possibly relating to the painting’s complex restoration history. ToF–SIMS’s ability to discern both organic and inorganic species via cross-sectional imaging was used to compare samples collected from Le Bonheur de vivre to artificially aged reference paints in an effort to gather mechanistic information relating to alteration processes that have been previously explored using μXANES, SR-μXRF, SEM–EDX, and SR-FTIR. The relatively high sensitivity offered by ToF–SIMS imaging coupled to the high spatial resolution allowed for the positive identification of degradation products (such as cadmium oxalate) in specific paint regions that have before been unobserved. The imaging of organic materials has provided an insight into the extent of destruction of the original binding medium, as well as identifying unexpected organic materials in specific paint layers.

Photochemistry of Artists’ Dyes and Pigments: Towards Better Understanding and Prevention of Colour Change in Works of Art

“…Computational simulations of the interaction of CdS with O 2 and/or H 2 Oalso showed that structural defects (i.e., Cd/S vacancies) at pigment surface are reasonably linked to the more complex photo-oxidation reactions observed in paintings. [21] Nevertheless,for the following reasons we are still far from at horoughly understanding of the reactivity of CdS in paint layer:1 )both CdSO 4 and other compounds,i dentified as secondary products,could instead already be present in the original paint formulations,a ssynthesis residues or additives; [15a] 2) it is not clear whether or not Cd À Cl species (likely the residues of the CdS synthesis) can promote self-oxidation; 3) it is not clear how the stability of CdY is affected by their differences in crystal structure and stoichiometry.M oreover, also the possible activity of CdY as photocatalyst deserves further investigation since the chalking phenomenon visible in JoyofLife [18,22] and in CdY mock-ups exposed to light and humidity [23] might be ascribed to the oxidative degradation of the binding medium.…”

Mass Spectrometry for Single-Cell Analysis

“…It has been noted that SIMS is a relatively tough ionization technique, and the molecular weight of the ionized species occurs in the narrow weight range. Therefore, it is well suitable for the study of lipids, small-molecule metabolites, molecular fragments, and elements (Angerer et al 2016;Aoyagi et al 2015;Taylor et al 2015;Voras et al 2015). Based on the ion intensity and quantity of the surface damage via an ion beam, SIMS is categorized into two different (static and dynamic) modes.…”

Zur Photochemie von Künstlerfarben: Strategien zur Verhinderung von Farbveränderungen in Kunstwerken

“…[18] Die Photooxidation von CdS-basierten Verbindungen zu CdSO 4 -d er wahrscheinlichste Abbauweg in der Gegenwart von O 2 und Feuchtigkeit [19] -w urde durch elektrochemische Messungen an CdS-Pulver bestätigt. Darüber hinaus muss auch die mçgliche Aktivitätv on CdY als Photokatalysator weiter erforscht werden, da das in Die Freude am Leben [18,22] und in CdY-Attrappen unter Lichtund Feuchtigkeitseinwirkung [23] beobachtete Verkreidungsphänomen auf den oxidativen Abbau des Bindemittels zurückgeführt werden kçnnte. [21] Dennoch sind wir weit entfernt von einem tiefgreifenden Verständnis der Reaktivitätv on CdS in Farbschichten, aus den folgenden Gründen:1)Sowohl CdSO 4 als auch andere Verbindungen, die als Folgeprodukte identifiziert wurden, kçnnten bereits in den ursprünglichen Farbformulierungen als Überbleibsel der Synthese oder als Additive vorhanden gewesen sein.…”

“…3) Es ist nicht klar, wie die Stabilitätd er CdYs von ihren Unterschieden in der Kristallstruktur und Stçchiometrie beeinflusst wird. Darüber hinaus muss auch die mçgliche Aktivitätv on CdY als Photokatalysator weiter erforscht werden, da das in Die Freude am Leben [18,22] und in CdY-Attrappen unter Lichtund Feuchtigkeitseinwirkung [23] beobachtete Verkreidungsphänomen auf den oxidativen Abbau des Bindemittels zurückgeführt werden kçnnte.…”