Publications by authors named "S Longelin"

This case study illustrates the analytical characterization of 12 academic nude paintings by Veloso Salgado, made between 1883 and 1893. The study was done with in situ methods (infrared reflectography and EDXRF) and benchtop equipment (Raman and FTIR microscopes and SEM-EDS). Infrared reflectography revealed underdrawings, painting style, execution method and retouched/restored areas.

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The present study characterizes the main deterioration mechanisms affecting the early 17th frescoes of Casa de Fresco, the only known example in Portugal of a semi-underground leisure room richly decorated with a balcony over a water well. Frescoes from the vault are at risk due to salt weathering and biodeterioration. The aim of the research was identification of the deterioration materials, determination of their origin, and their effect on the frescoes before future intervention.

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The objects of this study are various local charters (cartas de foral, in Portuguese) granted by Dom Manuel I, King of Portugal (1495-1521), which substituted for medieval ones and were intended to achieve an administrative unification. These are luxuriously illuminated manuscripts, and our study aims at obtaining a better understanding of the gilding and silvering techniques applied to the parchments, in which the forais were written, between 1500 and 1520. The combined use of microscopy and X-ray spectroscopy analyses allowed us to identify the vestigial materials used for making the parchments, including products such as salt (NaCl), lime (CaO), pumice stone (SiO2+Al2O3), and chalk (CaCO3).

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The analysis of a Portuguese "papier-mâché" sculpture depicting Saint Anthony is presented in this case study. Several questions were addressed such as the characteristics of the support, pigments used, and artistic technique in order to establish a possible timeline for its production. Qualitative analyses of the cross-sections and of the paper support were performed by optical microscopy using reflected light.

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In this work, we have built a portable X-ray fluorescence (XRF) spectrometer in a planar configuration coupled to a Raman head and a digital optical microscope, for in situ analysis. Several geometries for the XRF apparatus and digital microscope are possible in order to overcome spatial constraints and provide better measurement conditions. With this combined spectrometer, we are now able to perform XRF and Raman measurements in the same point without the need for sample collection, which can be crucial when dealing with cultural heritage objects, as well as forensic analysis.

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