The technology of copper-based red glass sectilia from the 2nd century ad lucius verus villa in rome

PD/BD/135053/2017This work aimed to investigate the origin of different red hues of Roman copper-based red opaque glass sectilia, to shed light on the production technology behind them. This objective was achieved by the depth study of the samples of glass sectilia, which decorated the villa of co-Emperor Lucius Verus (161–169 AD). These were selected for analysis due to their abundance, the certainty of their date and of their different red and orange hues. Using OM (optical microscopy), colourimetry and FORS (fibre optical reflectance spectroscopy) spectroscopy, four red and four orange hues were individuated. A set of representative samples for each hue was analysed by EPMA (electron probe microanalyses) to detect any correlation between colour and chemical composition. Crystalline phases were investigated through high-resolution FEG–SEM (field emission gun scanning electron microscope), µRaman spectroscopy and XRD, for the identification of colouring and opacifying agents and to understand how the different hues are affected by their shape, concentration and dimension. Sub-micrometric particles of metallic copper and cuprite crystals were identified as both the colouring and opacifying agents. These were not present in the same samples and were manufactured by two distinct colouring techniques, corresponding to two different glass chemical compositions. The size and the number of the colouring particles were the main factors that distinguished one hue from another. Although produced through different colouring techniques, some red samples appeared to be very similar to each other. These data enrich a period of the Roman age through some analyses and allow the identification of the type, as well as some of the production conditions of opaque red glass produced during 2nd century AD, which could be considered to be a period of transition from one technology to another.publishersversionpublishe

Grazing incidence X-ray reflectivity - a Round Robin test : Report of the International Commission on Glass (ICG) Technical Committee 19 "Glass Surface Diagnostics"

Densities and thicknesses of films of five different layer systems were determined in a grazing incidence X-ray analysis (GIXA) Round Robin test carried out by three industrial laboratories. The influence of both the experimental setup and the simulation software on these results is compared for the identical set of samples. Two approaches are adopted; firstly each laboratory measuring and simulating its own data and secondly each laboratory simulating the data that had been measured by another laboratory. The measured data from the three laboratories are analyzed and reasons proposed to explain the relatively minor differences between them. Comparisons are also made between the simulations produced from the two approaches to determine variations and any systematic bias between the three laboratories. Overall, good agreement in film densities and film thicknesses is found, demonstrating the high levels of accuracy that can be obtained from coating analysis using the GIXA technique

Le bore dans les glaçures des céramiques post-palisséennes

Le bore a été utilisé essentiellement à partir de la fin du xviiie siècle dans la formulation des verres et glaçures. Toutefois, sa présence en très faibles quantités dans certaines glaçures post-Renaissance, donc dès le xviie siècle, nous a incités à évoquer l’histoire de cet élément dans les matériaux vitreux. Nous tenterons de comprendre l’origine du bore dans ces glaçures et discuterons son impact sur les questions de datation et d’authentification des productions post-palisséennes.Boron was mainly used in the production of glass and glazes from the late 18th century onwards. However, its presence in very tiny quantities in certain post-Renaissance glazes, thus from the 17th century onwards, has prompted us to recall the history of this element in vitreous materials. We shall attempt to explain the origins of boron in these glazes and discuss its impact on the dating and authentication of post-Palissian production

Techniques d’opacification de l’émail au xixe siècle : nouvel éclairage apporté par le microscope à balayage à effet de champ

La Cité de la Céramique à Sèvres conserve des verres d’origines diverses utilisés au xixe siècle pour les peintures sur porcelaine et les émaux sur cuivre. Nous avons étudié neuf de ces verres opaques ou opalescents. Les observations au microscope électronique à balayage (MEB) montrent qu’ils contiennent des particules dont les dimensions sont de l’ordre de 0,1 µm pour les verres opalescents, nettement plus grandes dans le cas des verres opaques. La nature de ces particules a été déterminée par spectroscopie par dispersion d’énergie (energy dispersive spectroscopy – EDS) et par diffraction des rayons X (DRX). Dans certains cas, des solutions classiques (cassitérite, antimoniate de calcium) ont été utilisées. Dans d’autres cas, des compositions plus complexes (arséniate de plomb pouvant contenir du phosphore, du calcium…), voire pratiquement inconnues (antimoniate de potassium et silicium, phosphate de sodium et calcium) ont été mises en évidence. Le microscope à balayage équipé d’un canon à effet de champ est un outil précieux pour visualiser la phase opacifiante, en déterminer la granulométrie et en estimer la composition.The Cité de la Céramique, in Sèvres, has a collection of glass of diverse provenance used in the 19th century for painting on porcelain and enamelling on copper. We studied nine of these opaque and opalescent glasses. Observation obtained via scanning electron microscopy showed that opalescent glass contained particles measuring about 0.1 µm, while particles in opaque glass were much larger. The nature of these particles was determined by energy dispersive spectroscopy (EDS) and by X-ray diffraction (XRD). In some cases, conventional solutions (cassiterite, calcium antimonate) had been used. In other cases, more complex compositions (lead arsenate containing phosphorus, calcium…), or practically unknown compositions (potassium silicon antimonate, sodium calcium phosphate) came to light. Fitted with a field emission* gun, the scanning electron microscope is a valuable tool for observing the opacifier and determining the size and the composition of the particles.*. The field emission electron gun produces a distinctly finer electron beam than the one formerly obtained using a tungsten filament emitter. The lateral resolution thus obtained is in the order of 1 nm

Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

PD/BD/135053/2017 UID/EAT/00729/2019This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.publishersversionpublishe

Effect of Zn2+ and Cu2+ -bearing salts on the dissolution of silicate glasses

International audienc

Multi-method characterization of soda-lime glass corrosion : Part 2. Corrosion in humidity Report of the International Commissionon Glass (ICG) Subcommittee of Technical Committee 19 "Glass Surface Diagnostics"

As-received and cleaned soda-lime glass surfaces corroded in high relative humidity of 95 % at a temperature of 60 °C for times up to one week are investigated by means of TOF-SIMS, SNMS, XPS, NRA, ERD, RBS, GIXR, AFM, SEM and optical microscopy. Distinct differences in the corrosion behavior are observed for as-received and cleaned glass surfaces. Changes in element concentration in the glass interface and in the topography of the glass surfaces are described for different exposure times in humidity. They are combined with variations in density of the modified surface layer. Cleaning before the corrosion treatment drastically reduces degradation; cleaning after the corrosion treatment can restore the surface

Discerning differences: Ion beam analysis of ancient faience from Naukratis and Rhodes

Faience technology was known in Egypt since the Predynastic Period and practiced for a period also in Bronze Age Greece, but, having been lost, was reintroduced to the Greek world only in the first half of the first millennium BC. The Greek island of Rhodes and the Greek-Egyptian trade harbour of Naukratis in the Nile Delta are suspected to be key centres of early Greek-style faience production, exporting amulets and vessels across the Mediterranean region. Yet the nature and scale of their production and their role in technology transfer, vis-à-vis Egyptian and Levantine/Phoenician production, remain little understood. The main aim of this study was to discover whether it is possible to define chemical characteristics for the faience produced and found at Naukratis, and to use this data to differentiate between artefacts produced here and elsewhere.A programme of ion beam (PIXE and PIGE) analysis was conducted under the CHARISMA transnational access scheme, known to be a suitable tool for studying ancient vitreous artefacts as it provides a non-destructive means of obtaining precise and accurate quantitative compositional data. Both the internal body of damaged objects as well as the outer glaze layer were analysed, of which only the latter are discussed here. The results of this study indicate that the faience found at both Naukratis and on Rhodes is compositionally similar. However, some small differences were found in the raw materials used in its production which may help us to better characterise the production of different faience manufacturing centres.La technique de la faïence, connue en Égypte depuis la période prédynastique et utilisée également pendant un certain temps en Grèce à l’âge du Bronze, s’est perdue ensuite. Elle ne fut réintroduite dans le monde grec que vers la première moitié du Ier millénaire av. J.-C. On pense que l’île grecque de Rhodes et le port marchand gréco-égyptien de Naucratis dans le delta du Nil furent de grands foyers de production de faïences, exportant des amulettes et des vases dans tout le pourtour méditerranéen. Cependant, la nature et l’ampleur de leur production restent mal connues, de même que leur rôle dans la diffusion des techniques de fabrication en Égypte et au Levant/Phénicie. Cette recherche avait pour principal objectif de savoir s’il était possible de déterminer les caractéristiques chimiques des faïences fabriquées et découvertes à Naucratis, afin de mieux discerner les différences entre les objets produits sur ce site et ailleurs.Nous avons pu conduire des analyses par faisceaux d’ions (méthodes PIXE et PIGE) dans le cadre du programme européen CHARISMA d’accès transnational, offrant un outil adapté à l’étude des objets antiques vitrifiés, car c’est un moyen non-destructeur de recueillir des données quantitatives précises et fiables sur la composition des matériaux. Nous avons analysé aussi bien la pâte, à l’intérieur d’objets abîmés, que la glaçure extérieure, et c’est cette dernière qui est décrite ici. Les résultats de notre étude font apparaître une composition similaire pour les faïences découvertes à Naucratis et à Rhodes. Quelques petites variations découvertes dans les matières premières employées pourraient faciliter la caractérisation des faïences fabriquées dans les différents foyers de production

Le verre de la pyramide du Louvre

Pour répondre aux exigences de l’architecte Ieoh Ming Pei, le choix du verre de la pyramide du Louvre a posé des problèmes scientifiques et techniques en termes de composition, couleur, procédé d’élaboration, etc. Finalement, ce choix s’est porté sur un verre sodocalcique classique, mais très pauvre en fer (< 200 ppm). Pour éviter toute teinte résiduelle, il a été nécessaire de décolorer le verre. La décoloration classique au manganèse n’a pas pu être utilisée à cause des risques de solarisation, et c’est la décoloration au sélénium qui a été retenue. Le verre a été élaboré et laminé à l’usine de Saint-Gobain (Aisne), puis douci et poli dans une autre entreprise en Angleterre. Il a ensuite été feuilleté : deux plaques de verre de 10 mm chacune prennent en sandwich une mince feuille de polymère, comme dans les pare-brise modernes ou les verres anti-effraction.To meet the demands of architect Ieoh Ming Pei, the choice of glass for the Louvre Pyramid posed scientific and technical problems as regards composition, colour, production process, etc. In the end, a classic soda-lime glass with a very low iron content (< 200 ppm) was chosen. To avoid any residual tinted effects, the glass needed to be decoloured. The conventional process of removing colour with manganese could not be used because of the risk of solarisation. Selenium was thus employed to decolour the glass. Manufactured and laminated in the Saint-Gobain glassworks (Aisne, France), the surface was then polished and finished by another company in England. Then, a layer of polymer foil was sandwiched between two sheets of 10 mm-thick glass, as in modern vehicle windscreens or burglar-proof glass

Techniques d'opacification de l'émail au XIXe siècle : nouvel éclairage apporté par le microscope à balayage à effet de champ

International audienceThe Cité de la Céramique, in Sèvres, has a collection of glass of diverse provenance used in the 19th century for painting on porcelain and enameling on copper. We studied nine if these opaque and opalescent glasses. Observation obtained via scanning electron microscopy showed that opalescent glass contained particles measuring about 0.1 µm, while particles in opaque glass were much larger. The nature of these particles was determined by energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). In some cases, conventional solutions (cassiterite, calcium antimonate) has been used. In other cases, more complex compositions (lead arsenate containing phosphorus, calcium...), or practically unknown compositions (potassium silicon antimonate, sodium calcium phosphate) came to light. Fitted with a field emission gun, the scanning electron microscope is a valuable tool for observing the opacifier and determining the size and the composition of particles.La Cité de la Céramique à Sèvres conserve des verres d'origines diverses utilisés au XIXe siècle pour les peintures sur porcelaine et les émaux sur cuivre. Nous avons étudié neuf de ces verres opaques ou opalescents. Les observations au microscope électroniques à balayage (MEB) montrent qu'ils contiennent des particules dont les dimensions sont de l'ordre de 0,1 µm pour les verres opalescents, nettement plus grandes dans le cas des verres opaques. La nature de ces particules a été déterminée par spectroscopie par dispersion d'énergie (energy dispersive spectroscopy - EDS) et par diffraction des rayons X (DRX). Dans certains cas, des solutions classiques (cassitérite, antimoniate de calcium) ont été utilisées. Dans d'autres cas, des compositions plus complexes (arséniates de plomb pouvant contenir du phosphore, du calcium...), voire pratiquement inconnues (antimoniate de potassium et de silicium, phosphate de sodium et calcium) ont été mises en évidence. Le microscope à balayage équipé d'un canon à effet de champ est un outil précieux pour visualiser la phase opacifiante, en déterminer la granulométrie et en estimer la composition