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In situ Raman spectroscopy analysis combined with Raman and SEM‐EDS imaging to assess the conservation state of 16th century wall paintings
Author(s) -
Irazola Mireia,
Olivares Maitane,
Castro Kepa,
Maguregui Maite,
MartínezArkarazo Irantzu,
Madariaga Juan Manuel
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4036
Subject(s) - raman spectroscopy , chemical imaging , spectrometer , gypsum , analytical chemistry (journal) , conservation , mortar , palette (painting) , materials science , scanning electron microscope , x ray fluorescence , chemistry , optics , fluorescence , geology , environmental science , art , composite material , physics , environmental chemistry , remote sensing , hyperspectral imaging , visual arts , environmental planning
A multianalytical methodology based on Raman spectroscopy was proposed to carry out the analysis of two wall paintings located in Saint Andrew Church (Biañez, Biscay) and Saint John the Baptist Church (Axpe, Biscay). On the one hand, Raman, assisted with energy‐dispersive X‐ray fluorescence and diffuse reflectance infrared portable spectrometers, was used in the in situ analysis of original support materials and pigments as well as in the identification of the degradation products. Such portable spectroscopic techniques allow identifying the areas to be sampled in order to perform deeper analyses by means of Raman chemical imaging and scanning electron microscope equipped with an energy dispersive spectrometer. Cross‐sections were performed with the micro‐samples taken in the areas of interest. Thereby, the colour palette, the mortar, the restoration processes and the degradation products were determined. The Raman analyses revealed that the transformation of gypsum into anhydrite in the intonaco layer was responsible for the detachment observed in the wall paintings from Axpe. Several hypotheses such as the harmful effect of previous restorations have been considered as precursor of the damage. Besides, decaying products, such as nitrates and oxalates, derived from physicochemical processes in the raw materials were also detected. Copyright © 2012 John Wiley & Sons, Ltd.