Portable Raman monitoring of modern cleaning and consolidation operations of artworks on mineral supports.
Any restoration performed on cultural heritage artworks must guarantee a low impact on the treated surfaces. Although completely risk-free methods do not exist, the use of tailor-made procedures and the continuous monitoring by portable instrumentation is surely one of the best approaches to conduct a modern restoration process. In this work, a portable Raman monitoring, combined sometimes with spectroscopic techniques providing the elemental composition, is the key analysis technique in the three-step restoration protocol proposed: (a) in situ analysis of the surface to be treated (original composition and degradation products/pollutants) and the cleaning agents used as extractants, (b) the thermodynamic study of the species involved in the treatment in order to design a suitable restoration method and (c) application and monitoring of the treatment. Two cleaning operations based on new technologies were studied and applied to two artworks on mineral supports: a wall painting affected by nitrate impact, and a black crusted stone (chalk) altarpiece. Raman bands of nitrate and gypsum, respectively, decreased after the step-by-step operations in each case, which helped restorers to decide when the treatment was concluded, thus avoiding any further damage to the treated surface of the artworks.
Kimika Analitikoaren Saila-Department of Analytical Chemistry, Faculty of Science and Technology, University of the Basque Country (EHU/UPV), P.O. Box 644, 48080 Bilbao, Basque Country, Spain. irantzu.martinez@ehu.es
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I
Martínez-Arkarazo
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A
Sarmiento
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M
Maguregui
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K
Castro
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Madariaga