Monico Letizia, Cartechini Laura, Rosi Francesca, Chieli Annalisa, Grazia Chiara, De Meyer Steven, Nuyts Gert, Vanmeert Frederik, Janssens Koen, Cotte Marine, De Nolf Wout, Falkenberg Gerald, Sandu Irina Crina Anca, Tveit Eva Storevik, Mass Jennifer, de Freitas Renato Pereira, Romani Aldo, Miliani Costanza
CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy.
SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy.
Sci Adv. 2020 May 15;6(20):eaay3514. doi: 10.1126/sciadv.aay3514. eCollection 2020 May.
The degradation of cadmium sulfide (CdS)-based oil paints is a phenomenon potentially threatening the iconic painting (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.
基于硫化镉（CdS）的油画颜料降解是一种可能威胁爱德华·蒙克（Edvard Munch）于1910年创作的标志性画作（收藏于奥斯陆蒙克博物馆）的现象，目前人们对此仍知之甚少。在此，我们提供了硫酸镉和亚硫酸盐作为原始基于CdS的颜料的蚀变产物存在的证据，并探讨了导致这种转变的外部环境和内部因素。对该画作进行的宏观原位非侵入光谱研究，结合对一个微样本和人工老化模型的同步辐射X射线显微光谱研究表明，水分和可移动的氯化合物是促进CdS氧化的关键因素，而光（光降解）起的作用较小。此外，在受潮情况下，涉及颜料溶解、在颜料中迁移以及水溶性相再结晶的平行/二次反应与硫酸镉的形成有关。
