Efficiency of combined MA-XRF and CXRF to give nondestructive insights about changes of a historical painting

Abstract

Historical paintings with important iconographical changes represent an analytical challenge. Considering the case study of a fifteenth-century French painting studied during its restoration, the efficiency of a combined noninvasive approach of two-dimensional scanning macro-X-ray fluorescence imaging (MA-XRF) and a laboratory-based depth-resolved confocal micro-X-ray fluorescence (CXRF) is discussed. Large chemical maps of several elements were obtained by MA-XRF, enabling the identification of zones of interest representing changes in the painting composition. In these areas, depth profiles were measured with CXRF, allowing to evidence overlaying paint layers. The advantages of this technique are that it can give direct information on the stratigraphy of paint layers in a nondestructive way and can reduce the sampling needed, as well as increase the locations analyzed (in our study twenty-two depth-resolved scans). These results complement information obtained by scanning electron microscopy coupled with an energy-dispersive X-ray analyzing system (SEM–EDX) on three cross-sectional samples taken in the areas of interest. Additionally, the three cross sections of the painting were studied by CXRF lateral scans (y) in order to evaluate the efficiency of the CXRF analyses against SEM–EDX. The study shows the benefits of the combination of MA-XRF and CXRF for analyzing painting compositions, as such a high number of cross sections would have been impossible to sample. From an art-historical and conservation perspective, this combined study provides an understanding of the original painting’s paint sequence and its later retouches, helping to make informed conservation treatment decisions. Graphic Abstract

2023 atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…In the field of cultural heritage , the use of both confocal XRF spectrometry and macroXRF spectrometry, together with SEM-EDX cross-sectional analysis, enabled Tapia et al 19 to study hidden layers in the painting Virgin and Child surrounded by saints and donor which is currently conserved in the Louvre Museum, Paris. The fact that macroXRF spectrometry did not offer depth resolution had previously hampered the collection of depth selective information on a painting's stratigraphy.…”

Angle-Dependent XRF Analyses: Pros and Cons of a Novel Technique in the Field of Cultural Heritage

“…The former irradiates the sample, and the latter collects the fluorescence signal emitted by the sample. In principle, no other requirements are needed; for this reason, XRF can be conducted in situ, directly on the artifact [35][36][37][38][39][40][41], without the need for sample transportation. Due to the absorption of air and the detector efficiency, XRF can generally detect atoms heavier than silicon, up to uranium; however, some spectrometers can detect elements as light as fluorine [42].…”

Combined Scanned Macro X-Ray Fluorescence and Reflectance Spectroscopy Mapping on Corroded Ancient Bronzes

“…When approaching objects of cultural importance, the use of non-invasive analytical methodologies with portable instruments to study material composition is essential [10,11], especially if you want to perform extensive analyses on the whole, or most of, the surface of the artifact [12][13][14][15][16]. This approach is commonly used in the case of paintings in which, before taking samples of material to carry out any studies on the stratigraphy and organic compounds, localized or mapping analyses are carried out with non-invasive spectroscopic techniques such as X-ray fluorescence (XRF) and reflectance spectroscopy in the visible and infrared range (VIS-NIR-SWIR RS) [17][18][19][20][21][22].…”