Portrait of an Etruscan Athletic Official: A Multi-Analytical Study of a Painted Terracotta Wall Panel

The Getty’s Etruscan painted terracotta wall panel, Athletic Official, recently has been speculated to be associated with a Caeretan wall panel depicting a Discobolus based on a shared iconography. To better understand the materials and techniques used to create the Getty panel and investigate its relation to extant Etruscan painted terracotta panels, a multi-analytical study was conducted, using broadband visible, IR, and UV imaging, along with scanning MA-XRF, FORS, Raman, SEM-EDS, and XRD analytical techniques. The analytical results together with PCA analysis suggest the clay support of the Getty panel is most similar in composition to that of panels from Cerveteri. A manganese black was identified in the decorative scheme; not commonly employed, this appears to be an important marker for the workshop practice in Cerveteri. Most significantly, the use of MA-XRF scanning allowed for invisible ruling lines on the Athletic Official, presumably laid down at the earliest stages of the creation of the panel, to be visualized. Taken together, the results of this study provide new insights into Caeretan workshop practice as well as provide a framework for better understanding the design and execution of Etruscan polychromy

A 'true' Roman glass: evidence for primary production in Italy

Raw natron glass was traded throughout the Roman Empire as chunks, remelted, coloured and/or decoloured if desired, and shaped into finished objects in secondary workshops. Primary production centres, active from the 4th to 8th century AD, were identified in Egypt and Syro-Palestine. However, the location of primary production centres in the Hellenistic and early Roman world is still a subject of intense debate. Ancient authors, such as Strabo and Pliny the Elder, suggest that glassmaking sands were found near the Belus River (Israel) and in Egypt, but also along the coasts of Spain and France and near the mouth of the Volturno River (Italy). Primary production in the western Mediterranean is not supported by any direct archaeological evidence so far, but the possibility to produce glass using sand raw materials from these regions has been recently evaluated. Results show that suitable glass making beach sands are far from common, and are mainly located in a few locations in Basilicata and Apulia regions (SE Italy) and Tuscany (W Italy), as well as in southern Spain and Provence (France).Over the past decades, different approaches have been attempted to provenance the raw materials used in glass making and to determine the locations of primary production centres. Particularly promising is the combined use of Sr and Nd isotopic analyses and elemental analyses, with particular attention to sand-related trace elements such as Ti, Cr, Sr, Zr, and Ba.The present work investigates the possible existence of primary Roman glass making centres along the Italian peninsula. The sample set includes a total of 176 glass fragments excavated in the Roman towns of Augusta Praetoria, Potentia, Pompeii and Herculaneum, and materials from the cargos of the Iulia Felix and Embiez shipwrecks. These samples date from the 1st to 4th century AD and include both coloured and colourless glass.The extraordinary compositional consistency of Roman natron glass analyzed here and the principal compositional groups widespread on Mediterranean sites tend to support the model of the centralised production, organized in a small number of primary workshops, which supplied raw glass to a great number of secondary workshops where the glass was re-melted and shaped into objects. The emerald green glasses appear to represent an exception. Their different compositions, that may involve the use of plant ash rather than natron as a fluxing agent, reflects the use of a dedicated technology for the production of this particular colour present only in the 1st century AD. Manganese and antimony, the two main decolouring agents in ancient times, were used for making colourless glasses. The study defines a timeline for the use of the two decolouring agents, pointing to the use of manganese already during the 1st century AD, in contrast to its later introduction suggested in literature.To explore the provenance of raw materials, a combined approach, using alumina contents, trace elements patterns and Sr-Nd isotopic signatures, has been followed. The results obtained for the glass samples discussed here have been compared to the known 4th to 8th century AD Egyptian and Syro-Palestinian primary glasses and to a database which includes suitable glass making sands across the Mediterranean. These data suggest that the vast majority of Roman glasses analysed in this study were likely produced in workshops situated along the Syro-Palestinian coasts, while a different silica source is suggested for Sb-decoloured glasses. At present neither Syro-Palestinian nor southern Italian sands can be excluded. The use of different sand sources for Sb-decoloured glass indicates a careful selection of raw materials and the existence of specialized workshops for their production. The Augusta Praetoria glass samples are more difficult to interpret. The provenance of a silica source with high Cr content is still unclear, and neither the eastern Mediterranean nor the southern Italian hypothesis can be excluded at present.A significant part of this doctoral work also has been dedicated to the definition of a simple, rapid and practical analytical protocol for the isolation of Nd from complex glass matrixes. Accurate isotopic measurement requires target element purification prior to mass spectrometric analysis using MC-ICP-MS. Whereas the extraction chromatography separation of Sr from concomitant matrix is well established, this was not the case for Nd. A series of tests were performed to better understand the dependence of the elution profile on the amount of resin and column type. Different column shapes indeed modify the elution profile. The selection of the correct HCl concentration to be used for Nd elution has proved to be of maximum importance. Small differences in HCl concentration modify significantly the elution rate, and could be responsible for sample loss. Lastly, the possibility to regenerate up to four times the resins involved in the separation protocol has been evaluated.status: publishe

The production of Roman glass with western Mediterranean sand raw materials: preliminary results

Pliny the Elder’s ‘Natural History’ is often cited in studies of ancient natron glass production. Pliny describes the production of glass using sand from the Belus River in Israel and the Volturno River in Italy. He also mentions that glass was similarly made in France and Spain. However, no direct archaeological evidence has ever been found to support glass production in these regions. In this study we investigate the possible existence of a Roman primary glass industry in the western Mediterranean, based on the occurrence of suitable sand raw materials. 178 beach sands from Spain, France and Italy are evaluated for their suitability for glass production by calculating the composition of hypothetical glasses made from these sands and comparing them to Roman natron glass. The results show that good glassmaking sands are far from common. Only six limited areas could be defined where suitable sand raw materials would have been available to the Roman glassmaker. The rest of the sands are unsuitable for glass production in their present form. The suitability of the suggested sands was checked by performing a series of melting experiments, which provide further insights in the way Roman glass makers would have had to prepare their raw materials and the used batch recipes.status: publishe

Mediterranean sand deposits as a raw material for glass production in Antiquity

status: publishe

Portrait of an Etruscan Athletic Official: A Multi-Analytical Study of a Painted Terracotta Wall Panel

The Getty’s Etruscan painted terracotta wall panel, Athletic Official, recently has been speculated to be associated with a Caeretan wall panel depicting a Discobolus based on a shared iconography. To better understand the materials and techniques used to create the Getty panel and investigate its relation to extant Etruscan painted terracotta panels, a multi-analytical study was conducted, using broadband visible, IR, and UV imaging, along with scanning MA-XRF, FORS, Raman, SEM-EDS, and XRD analytical techniques. The analytical results together with PCA analysis suggest the clay support of the Getty panel is most similar in composition to that of panels from Cerveteri. A manganese black was identified in the decorative scheme; not commonly employed, this appears to be an important marker for the workshop practice in Cerveteri. Most significantly, the use of MA-XRF scanning allowed for invisible ruling lines on the Athletic Official, presumably laid down at the earliest stages of the creation of the panel, to be visualized. Taken together, the results of this study provide new insights into Caeretan workshop practice as well as provide a framework for better understanding the design and execution of Etruscan polychromy

The Sr-Nd isolation procedure for subsequent isotopic analysis using multi-collector ICP-mass spectrometry in the context of provenance studies on archaeological glass

Sr and Nd isotopic analysis of glass can be relied upon to unravel the provenance of the flux component and the sand used in the manufacturing of archaeological glasses, respectively. For a reliable isotopic analysis of the target elements using multi-collector ICP-mass spectrometry, the target elements need to be isolated from the matrix to permit adequate correction for instrumental mass discrimination. In this paper, a simple, fast and reliable analytical method for the isolation of Sr and Nd from complex sample matrixes such as archaeological glasses is proposed. Special attention is focused on the Nd isolation protocol, with the definition of TRU-Spec and Ln-Spec resin bed volumes and of an appropriate HCl concentration to optimize Nd elution from the column

Casting Light on 20th-Century Parisian Artistic Bronze: Insights from Compositional Studies of Sculptures Using Hand-Held X-ray Fluorescence Spectroscopy

In the 19th and early 20th centuries, Paris was home to scores of bronze foundries making it the primary European center for the production of artistic bronzes, or bronzes d’art. These foundries were competitive, employing different casting methods—either lost-wax or sand casting—as well as closely guarded alloy and patina recipes. Recent studies have demonstrated that accurate measurements of the metal composition of these casts can provide art historians of early 20th-century bronze sculpture with a richer understanding of an object’s biography, and help answer questions about provenance and authenticity. In this paper, data from 171 20th-century bronzes from Parisian foundries are presented revealing diachronic aspects of foundry production, such as varying compositional ranges for sand casting and lost-wax casting. This new detailed knowledge of alloy composition is most illuminating when the interpretation of the data focuses on casts by a single artist and is embedded within a specific historical context. As a case study, compositional analyses were undertaken on a group of 20th-century posthumous bronze casts of painted, unbaked clay caricature portrait busts by Honoré-Victorin Daumier (1808⁻1879)

Things that travelled - a review of the Roman glass from Northern Adriatic Italy

Abstract presentato al Convegno "Things that Travelled - Mediterranean Glass in the First Millennium AD", 28-29 November 2014, London (UK)