A study on Correggio wall paintings: characterization of technique and materials of Abbey Church of S. Giovanni Evangelista in Parma, Italy

This study deals the materials of the sub- arch of the Del Bono chapel of the Abbey Church of S. Giovanni Evangelista in Parma, Italy, datable around 1523. The author of the painting is Antonio Allegri, known as Correggio (1489 – 1534), considered one of the greatest painters of the sixteenth century. Optical microscopy, micro-Raman spectroscopy, micro-Fourier Transform Infrared spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and gas chromatography coupled with mass spectrometry were selected in order to provide the higher set of significant data, limiting as much as possible sampling. The analysis has allowed to identify the pigments, characteristic of the epoch. The Correggio’s palette is composed by mineral pigments, sometimes expensive such as lapis lazuli, azurite and cinnabar, together with a wide range of earths or by synthetic pigments like smalt blue. From the amino acid content determination through GC/MS it was shown that, for all samples examined, the protein fraction is to be attributed to the presence of a mixture of egg and animal glue, present as binders in the samples containing lazurite, smalt, hematite, green earth and goethite. This allows to assume the use of a secco technique, also with pigments that do not need the employment of organic binding media on wall. For the gilding sample the hypothesis is that Au foil had been applied on a brown background where the Au foil is applied on the oil-based missione

Comparison of seven portable Raman spectrometers : beryl as a case study

In this paper, a series of beryl varieties with the accent on emeralds was investigated using seven portable Raman spectrometers equipped mainly with 785- and 532-nm excitation lasers. Additionally, one dual system and a new portable sequentially shifted excitation Raman spectrometer were applied. The advantage of using handheld instrumentation for investigations to be carried out outside the laboratory is well documented. For major part of beryls (emeralds and aquamarines), the most intense Raman bands are found at correct positions +/-2 to 4cm(-1) using all the instruments (with the exception of one). Unambiguous identification of beryls is ensured by obtaining the strong characteristic of Raman features (1070 and 686 cm(-1)) of the whole spectrum. Spectroscopic performance and differences existing between the instruments not only from the construction and ergonomic point of view are discussed. All the instruments tested EzRaman-I Dual (Enwave Optronics), RaPort (EnSpectr), FirstGuard (Rigaku), FirstDefender XL and FirstDefender RM (Thermo Scientific), Inspector Raman (Delta Nu) and Bravo (Bruker) can be used for common gemmological and mineralogical work in situ. Two instruments (the RaPort and the sequentially shifted excitation Raman spectrometer Bravo) allow recording excellent quality Raman spectra comparable with laboratory dispersive Raman microspectrometers

Methodological evolutions of Raman spectroscopy in art and archaeology

During the last decades, Raman spectroscopy has grown from research laboratories to a well-established approach that is increasingly often used in archaeometry and conservation science

The contribution of archeometry in characterization of decorative materials from the site of Villa di Teodorico in Galeata (Italy)

Villa di Teodorico in Galeata (Forlì-Cesena, Emilia Romagna) is an important archeological site in the north of Italy occupied from sixth century BC to twelfth century AD. The most interesting results concern the Roman age, when a large villa was built, and the late antiquity, when the Ostrogothic king Theodoric decided to build in this area his palatium (early sixth century AD). The archeometric investigation was performed on Roman wall paintings fragments and on late antique glass sectilia fragments belonging to Palazzo di Teodorico by using a multi-technique approach that included micro-Raman spectroscopy, scanning electron microscopy with energy-dispersive spectroscopy, X-ray powder diffraction, UV–visible–NIR diffuse reflectance spectrophotometry with optic fibers and optical stereo-microscopy. This analytical approach allowed the identification of all components, collecting molecular, elemental, microscopic, morphological and chromatic data. The characterization of samples supplied essential archeological, historical and technological information. The production techniques and the rich materials employed suggest the importance of the site in different periods. The evolution of the manufacturing technologies and the possible trade routes mainly during late antique period are witnessed by the change in the raw materials. Graphical abstract: [Figure not available: see fulltext.]

Multi-stage rodingitization of ophiolitic bodies from Northern Apennines (Italy): Constraints from petrography, geochemistry and thermodynamic modelling

n/

Portable Raman Spectrometer for in situ analysis of asbestos and fibrous minerals

Asbestos inhalation is associated with fatal respiratory diseases and raises concerns from the perspective of workplace safety and environmental impacts. Asbestos and asbestos-like minerals naturally occur in rocks and may become airborne when outcrops or soils are disturbed by anthropic activities. In situ detection of these minerals is a crucial step for the risk evaluation of natural sites. We assess here whether a portable Raman spectrometer (pRS) may be used in the identification of asbestos and asbestos-like minerals at the mining front during exploitation. pRS performance was tested at three geologically different mining sites in Italy and New Caledonia and compared with a high-resolution micro-Raman spectrometer (HRS). About 80% of the overall in situ analyses at the mining front were successfully identified by pRS, even when intermixed phases or strongly disaggregated and altered samples were analyzed. Chrysotile and tremolite asbestos, asbestos-like antigorite, and balangeroite were correctly detected during surveys. The major difficulties faced during in situ pRS measurements were fluorescence emission and focussing the laser beam on non-cohesive bundles of fibers. pRS is adequate for discriminating asbestos and asbestos-like minerals in situ. pRS may support risk assessment of mining sites to better protect workers and environmen

Micro-Raman mapping of the polymorphs of serpentine

Serpentinites are rocks, often used in buildings, formed in large extent by minerals of the serpentine group: chrysotile, antigorite, lizardite, and polygonal serpentine. The fibrous type (e.g. chrysotile) of serpentine group minerals, along with several amphibole varieties (e.g. actinolite and tremolite), are the major components of asbestos family. The exposure to fine fibrous asbestos powder is linked to diseases such as pleural mesothelioma and asbestosis. The identification of the main varieties of the serpentine group, laminated or fibrous, becomes an issue of great interest for public health. This work introduces an analytical strategy able to distinguish the different serpentine polymorphs directly on the sample, allowing the analysiswithin their textural environment, evidencing at themicrometer scale the mineral reactions of the phases. Samples coming from the Koniambo massif (Grande Terre Island, New Caledonia) were studied by means of optical microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, and Raman spectroscopy. Raman peaks observed in the high wavenumber spectral range of 3550–3850 cm-1, associated with OH stretching vibrations, allow the iscrimination of the all four serpentine varieties. The relationship between the different varieties of serpentine, at a micrometric scale, in complex samples, has been investigated by two-dimensional Raman mapping

The Alps as the main source of sand for the Late Miocene Lake Pannon (Pannonian Basin, Croatia)

The provenance of the Upper Miocene sandstones from the Sava and Drava depressions of the North Croatian Basin was investigated using petrographic, geochemical, and heavy mineral analyses, including Raman spectroscopy. The study of these sandstones, which represent important oil and gas reservoirs in Croatia, allowed reconstruction of the Late Miocene source-to-sink model of the Lake Pannon drainage system and the evolution of the southwestern Pannonian Basin. The studied feldspatho-litho-quartzose sandstones consist of a mixture of sedimentary, metamorphic, and igneous detritus. Heavy-mineral assemblages are dominated by almandine-rich garnet with apatite, epidote, tourmaline, rutile, zircon, staurolite, and zoisite, indicative of low to medium-grade metamorphic source rocks. Higher concentrations of Ca and Mg than in the Upper Continental Crust standard (UCC) additionally reflect the abundance of limestone and dolostone rock fragments as well as carbonate cement. Geochemical compositional variations between sandstone samples from the Sava and Drava depressions primarily stem from diagenetic processes. CIX and alpha values indicate only minor weathering. Compositional features indicate an orogenic source located in the Eastern Alps and primarily represented by Austroalpine and Penninic nappes. This research offers a novel perspective to distinguish the Upper Miocene reservoirs from other sedimentary units within the basin, contributing to a more comprehensive understanding of the regional geological dynamics and supporting future exploration projects also related to energy transition

Raman Analysis on 18th Century Painted Wooden Statues

A micro-Raman investigation on four wooden polychrome sculptures of Jan Geernaert (1704-1777), a Flemish sculptor who worked in Italy in the 18th century, is presented. The statues, representing the Holy Virgin Mary, with the infant Jesus in three of them, were created in the period 1750-1770 and are all made by poplar wood. The purpose of the micro-Raman investigations was to identify the original pigments used in 18th century, after later repainting interventions. In all statues, wood is covered by a groundwork, made by gypsum and animal glue. All pigments were identified, both in the original pictorial cover or in later repainted layers. Pigments were spread on a white lead layer (the so called imprimitura). Attention was particularly focused on the blue colours of the Holy Virgin mantle. In the external repainted layers, Prussian blue (Iron(II,III) hexacyanoferrate(II,III)) was found, together with ultramarine blue, a synthetic pigment, alternative to natural precious lapis lazuli, accessible on or after 1828. In one case, phthalocyanine blue is found, confirming a recent (later than 1930-35) restoration. The original skin colours are obtained by white lead and cinnabar (HgS), while the repainted layers are made by mixing chrome yellow (PbCrO4, synthesized in 1809), zinc yellow (ZnCrO4, 1809), red lead (Pb3O4), ultramarine blue, cinnabar, hematite (Fe2O3), goethite (-FeOOH), calcite (CaCO3) and white lead.Nous présentons une étude par micro-spectroscopie Raman sur la polychromie de quatre sculptures en bois de Jan Geernaert (1704-1777), sculpteur flamand qui a travaillé en Italie au 18ème siècle. Les statues, représentant la Sainte Vierge Marie, avec l'enfant Jésus pour trois d'entre elles, ont été réalisées entre 1750-1770 et sont toutes réalisées en peuplier. Le but de l’investigation par micro-spectroscopie Raman a été d'identifier les pigments d'origine et ceux issus des restaurations ultérieures. Pour toutes les statues, le bois est recouvert d’une couche de préparation réalisée par un mélange de gypse et de colle animale. Tous les pigments ont pu être identifiés, tant dans les couches picturales d'origine que sur les repeints plus tardifs. Les pigments ont été appliqués sur une couche de blanc de plomb (appelé imprimitura). Une attention particulière a été portée sur les couleurs bleus du manteau de la Sainte Vierge. Pour les couches externes correspondant aux repeints, nous avons identifié du bleu de Prusse (fer (II, III) hexacyanoferrate (II, III)) et de l'outremer, un pigment de synthèse disponible à partir de 1828 en alternative lapis-lazuli. Dans un cas, le bleu de phtalocyanine a été identifié, confirmant une restauration plus récente (post 1930-1935). La couleur d'origine de la peau est réalisée à partir de blanc de plomb et de cinabre (HgS). Les pigments présents dans les peintures plus récentes sont les suivants : jaune de chrome (PbCrO4 synthétisé en 1809), jaune de zinc (ZnCrO4, 1809), minium (Pb3O4), bleu outremer, cinabre, hématite (Fe2O3), goethite (-FeOOH), calcite (CaCO3) et blanc de plomb

Nondestructive Raman investigation on wall paintings at Sala Vaccarini in Catania (Sicily)

In this work, the results of a Raman campaign for studying seventeenth-century Sicilian frescoes, by using two portable Raman systems, equipped with different excitation sources (785 and 1064 nm), are proposed. The measurements were performed with the aim to provide an in situ diagnostic analysis of the wall paintings (in terms of colorants and preparation layer) and to support the conservators in the framework of the ongoing restoration. The combined use of the two Raman spectrometers has given a complete overview on the artist palette and on the state of preservation of frescoes, also informing us about the technique employed by the painter. Natural pigments as hematite, vermillion, goethite, lead red, lead white and carbon-based black pigments have been identified. Additionally, the application of a transitional Romanesque-Renaissance frescoes method has been noticed by the systematic combined presence of calcite and gypsum in the substrate. Finally, the analyses have highlighted the presence of degradation products, mainly related to alteration of lead-based pigments