Ana Cardoso

On the Use of the Unusual Green Pigment Brochantite (Cu 4 (SO 4 )(OH) 6 ) in the 16th-Century Portuguese- Flemish Paintings Attributed to The Master Frei Carlos Workshop

This paper reports an unusual green pigment, brochantite (Cu4(SO4)(OH)6), on 16th-century Portuguese-Flemish paintings, attributed to the Master Frei Carlos workshop. This green mineral is usually identified as an impurity or alteration product in the green pigments verdigris (Cu(CH3COO)2 nCu(OH)2) or malachite (CuCO3 Cu(OH)2). However, after thorough investigation with a broad range of analytical techniques, it became clear that, in this case, brochantite was applied as a pigment. The abundance, pigment granulometry, and pigment morphology suggest intentional use by this Portuguese-Flemish Master as a natural pigment rather than its accidental use as an alteration product. This seems to be a distinguishable feature to other painters (Flemish and Portuguese) working in Portugal at the beginning of the 16th century. The multi-analytical study of these easel paintings was first performed by physical imaging techniques and material characterization was carried out by optical microscopy, micro-Fourier-transform infrared-spectroscopy, micro-Raman spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry, and micro-X-ray diffraction analysis (XRD).

Multianalytical approach for the authenticity of an eighteenth-century Pascal Taskin harpsichord

This paper surveys a detailed characterization of a prestigious harpsichord brought into fashion in 1782 by Pascal Taskin. The implemented analytical methodology required the use of in situ Energy Dispersive X-Ray Fluorescence (EDXRF) for elemental analysis of the color palette, optical and SEM imaging (SE and BSE modes) for the layered structure identification, Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) for elemental composition of the inorganic compounds, Fourier Transform Infrared (FTIR) spectroscopy for some binders and THM-GC/MS as well for resinous layers identification. By cross-checking these data with those obtained by digital radiography, it was concluded that a true ravalement of the harpsichord was in fact undertaken and that, among more than five interventions applied to the instrument until the present day, the third one may correspond to the one performed at Pascal Taskins time.

Analytical characterization of the palette and painting techniques of Jorge Afonso, the great 16th century Master of Lisbon painting workshop

In this work, a study on a set of paintings from the most significant altarpiece assigned to Master Jorge Afonso (c. 1470-1540) painting workshop is presented. This altarpiece is composed by fourteen paintings made to the church of Convento de Jesus, in Setúbal, Portugal, and was made circa 1517-19/1530, according to art-history. This set of paintings is compared to one of the other most important Portuguese altarpieces from the 16th century: the panels of the Round Church of the Convento de Cristo, in Tomar, made circa 1510-1515. The aim of this study is to characterize the wooden support, pigments, ground layers materials and technique used in Jorge Afonso workshop by means of complementary analyses. A dendrochronological approach was made in order to corroborate (or not) the historical date initially assigned. Infrared photography (IRP) and reflectography (IRR) allowed the study of the underdrawing technique and macro photography (MP) was used to recognize overlapping layers technique. Cross-sections from the paintings were examined by optical microscopy (OM), and analyzed by μ-X-ray diffraction (μ-XRD), Energy Dispersive X-ray Fluorescence spectroscopy (EDXRF), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), micro-Raman spectroscopy (μ-Raman), micro-Fourier Transform Infrared spectroscopy (μ-FTIR), Pyrolysis Gas Chromatography Mass Spectrometry (py-GC/MS). The characterization of the palette and ground layers and the study of the overlapping of paint layers brought a new insight of the adopted painting techniques by the most important group of painters working in Portugal in the 16th century - the Lisbon workshop, leaded by Master Jorge Afonso.

Microscopy and Microanalysis of an Extreme Case of Salt and Biodegradation in 17th Century Wall Paintings

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. Scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDS) was used to determine salt morphology and microanalysis. The mineralogical characterization was performed by X-ray powder diffraction, complemented with µ-Raman and µ-Fourier transform infrared spectroscopy. Biological assessment was evaluated with optical microscopy and SEM-EDS. Bacterial and fungal isolation and identification were performed using standard culture media and methods according to Bergeys Manual of Systematic Bacteriology and from the Compendium of Soil Fungi. The results show that Ca and Ca-Mg carbonates from the paint renderings are the predominant salt species affecting the site. Bacterial strains from the genera Bacillus and Pseudomonas and fungal strains from the Cladosporium spp. and Penicillium spp. were isolated in the salt formations, within and between the mortar layers. Azurite, malachite, and smalt paint layers are the most affected by the weathering conditions.

In Situ High Temperature Texture Characterisation in NiTi Shape Memory Alloy Using Synchrotron Radiation

The aim of the present experiment was to analyse the structural evolution during annealing of Nickel-Titanium (Ni-Ti) SMA subjected to different thermomechanical treatments. As structural evolutions are accompanied by the changes in preferential orientations, pole figures were employed to study the in-situ conditions.