Imaging Secondary Ion Mass Spectrometry of a Paint Cross Section Taken from an Early Netherlandish Painting by Rogier van der Weyden

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• 作者：Katrien Keune and Jaap J. Boon
• 刊名：Analytical Chemistry
• 出版年：2004
• 出版时间：March 1, 2004
• 年：2004
• 卷：76
• 期：5
• 页码：1374 - 1385
• 全文大小：1340K
• 年卷期：v.76,no.5(March 1, 2004)
• ISSN：1520-6882

文摘

Static secondary ion mass spectrometry (SIMS) is introduced as an analytical technique for the examination ofpaint cross sections to obtain simultaneous informationabout the nature and distribution of pigments and thebinding medium from a single sample. A sample takenfrom the virgin's blue robe in the panel painting TheDescent from the Cross (Museo del Prado, Madrid) ofthe Early Netherlandish painter Rogier van der Weyden(1399/1400-1464) was selected for investigation.Data were compared with reference compounds andreference lead white linseed oil paint and egg temperapaint. The static SIMS technique gave position-sensitivemass spectra that were used to image the elementaldistribution of pigments and the molecular signature ofcomponents of the oleaginous binding medium. SIMS ionimages of sodium and aluminum superimposed with theblue pigment ultramarine and those of copper, lead, andcalcium with the position of the mineral pigments ofazurite, lead white, and chalk, respectively. Preservedmonocarboxylic acids of palmitic and stearic acids presentas fatty acids and fatty acid lead soaps pointed to the useof linseed oil as a binding medium. Images from theoleaginous binding medium fatty acids show a correlationwith the three main paint layers. The observed palmitic/stearic acid ratios for the two ultramarine layers andazurite layers are 1.3, 1.4, and 1.8, respectively. Fattyacids and fatty acid soaps show highest ion yields nearlead white, a mineral pigment that serves as a naturalchemical drier and is proposed to act as a template forthe initial grafting of the polyunsaturated triglycerides ofthe linseed oil. Almost no fatty acids were detected inother layers visible by light microscopy. The fatty acid leadsoaps point toward a mature ionomeric oil paint systemthat developed over centuries. SIMS evidence for eggtempera, still used in the 15th century, is not detected inthe paint cross section. SIMS images correlate well withSEM/EDX, FT-IR and light microscopic images and theSIMS spectral data additionally support the identificationof pigment particles, lead soaps, and other bindingmedium components.