Exploring the raw materials and technological practice to obtain red and black surfaces of Apulian red figure pottery by Raman and SEM‐EDS investigations

In this paper, 4th century BC Apulian red vases, from sites among the most relevant in Apulia (Italy), are studied by means of Raman spectroscopy. The effectiveness of this technique in the archaeometric research is emphasized, particularly regarding the manufacturing procedures and raw materials of black and red surfaces. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy (SEM-EDS) analyses are carried out jointly with Raman spectroscopy in order to complete the morphological and chemical information. The results show that two different clays have been employed for black gloss and ceramic body. The black gloss proves composed of the finest fraction of terre rosse—very common all over Apulia—with no organic material added to its clayey suspension. Traces of carbon found on the surfaces can be ascribed to fly ash deposited during the firing process. This research highlights that two more methods besides red engobe were used by Apulian potters to color red the surface of whitish/grayish vases realized with local raw materials, namely, the addition of either “miltos” or a clayey layer enriched in Fe oxides. A multistep firing (ox-red-ox), reaching the maximum temperature of about 900C, can be deduced from the different mineralogical phases identified through Raman. The possibility of gaining information on the hematite particles size from the position of its characteristic Raman bands is successfully investigated, allowing to get clues on the presence of a surface layer in a nondestructive manner by comparing the particle size there and in the ceramic body

CHARACTERIZATION OF SILK-COTTON AND WOOL-COTTON BLENDS PATTERN BOOKS BY FIBER OPTICS REFLECTANCE SPECTROSCOPY. THE BOOMING MARKET OF FIRST SYNTHETIC TEXTILE DYES IN EARLY 20th CENTURY

A remarkable number of early 20th century azo synthetic textile dyes was characterized by Fiber Optics Reflectance Spectroscopy (FORS). Items are part of silk-cotton and wool-cotton blends pattern books of Leopold Cassella & Co., a leading firm at that time. Focusing on early dyes from this privileged point of view, meant for us providing our own scientific contribution to restore luster to a historical period that represented the keystone from upmarket natural dyes to synthetic ones on a large scale. A selection of spectra on silk-cotton blend with the same dye concentration was compared color by color. In the case of wool-cotton blend textiles, two concentrations were available for each dye. Therefore, spectra comparisons between the same dyes used in silk-cotton and wool-cotton blends were carried out, as well as between the same dyes in different concentration in the case of wool-cotton textiles, simulating possible fading conditions. In addition, almost each analyzed dye was linked to its molecular structure. Finally, the obtained set of data has been statistically treated. The complete dataset was subjected to an exploratory analysis using PCA that exhibited an organization of the samples based on brightness and colors. The generation and validation of a PLS-DA model confirmed the recognizability of the samples based on color and pointed out the excellent conservation conditions implemented. The method provides a non-invasive, fast and low-cost approach for the recognition of azo dyes, based on the combined application of FORS, colorimetric parameters and chemometrics and lays the foundation for a reference database

Hematite as an Electrocatalytic Marker for the Study of Archaeological Ceramic Clay bodies: A VIMP and SECM Study**

[EN] The electrocatalytic effect exerted by hematite, a ubiquitous component of clay bodies, on the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) can be used to acquire information on archaeological ceramics. The solid-state voltammetric response of different hematite and ochre specimens, accompanied by SECM analysis in contact with 0.10 M HCl aqueous solution, is described. In air-saturated solutions, catalytic effects on the ORR and OER are accompanied by Fe(III)/Fe(II) and Fe(IV)/Fe(III) redox reactions. Such processes are conditioned by a variety of factors, the hydroxylation degree of the mineral surfaces being particularly influential, and exhibit significant variations upon heating the specimens between 300 and 900 degrees C. Voltammetric measurements carried out on a set of archaeological samples of Apulian red-figured pottery dated back within 5(th) and 4(th) centuries BCE permit to obtain site-characteristic voltammetric profiles.The work was carried out within the framework of project PID2020-113022GB-I00 which was financially support by Ministerio de Ciencia e Innovacion and Agencia Estatal de Investigacion (AEI) of the Spanish government.Doménech-Carbó, A.; Giannuzzi, M.; Mangone, A.; Giannossa, LC.; Di Turo, F.; Cofini, E.; Domenech Carbo, MT. (2022). Hematite as an Electrocatalytic Marker for the Study of Archaeological Ceramic Clay bodies: A VIMP and SECM Study**. ChemElectroChem. 9(2):59-68. https://doi.org/10.1002/celc.20210119759689

Reperti apuli a figure rosse provenienti dalla collezione Intesa Sanpaolo. Indagini su azioni di restauro e tecnologia di produzione

Questo lavoro si pone all’interno di un vasto progetto di studio sulla ceramica Apula a figure rosse (1-5) ed evidenzia l’importanza di una approfondita indagine archeometrica per un preciso e rigoroso restauro dei vasi. I reperti indagati, che coprono l’intero arco temporale di produzione (dall’Antico al Tardo Apulo), provengono da Ruvo di Puglia. Parte di essi fanno parte della collezione Intesa Sanpaolo (ex collezione Caputi) e sono custoditi nelle Gallerie d’Italia a Vicenza, altri fanno parte della collezione del Museo Archeologico di Napoli (MANN) e sono custoditi all’interno dello stesso Museo. Tutti i vasi indagati hanno subito interventi di restauri, non sempre documentati, per cui l’attenzione è stata posta sulla verifica di autenticità di alcune parti di essi, funzionale, nel caso dei vasi del MANN, alle successive operazioni di integrazione e restauro. Le indagini sono state condotte mediante una strategia multi-tecniche (Spettrometria di Massa al Plasma Induttivamente Accoppiata, Microscopia Elettronica a Scansione e microanalisi, Diffrazione a Raggi X e Spettroscopie Raman ed IR a trasformata di Fourier) ed hanno portato ad una completa caratterizzazione dei corpi ceramici e delle superfici. I risultati ottenuti, oltre a permettere di individuare parti non originali dei vasi (accuratamente mimetizzate durante i restauri ottocenteschi), hanno fornito importanti informazioni sulle tecniche di restauro impiegate durante il XIX secolo. Dal confronto poi con dati relativi a reperti della stessa classe, provenienti da siti archeologici pugliesi, è stato possibile confermare su base oggettiva la provenienza delle materie prime impiegate ed individuare differenze composizionali e tecnologiche fra vasi attribuiti a pittori diversi. Tutte queste informazioni potranno essere utili non solo nella progettazione di interventi di restauro per i vasi di questa classe ma anche per lo studio dei vasi decontestualizzati (es. vasi custoditi nei più importanti musei o appartenenti a collezioni private, in Italia e all’estero o provenienti dal mercato clandestino), che costituiscono, purtroppo, una parte rilevante di questa classe ceramica

The Distinctive Role of Chemical Composition in Archaeometry. The Case of Apulian Red Figure Pottery

Correlation of the scientific approach to the archaeological investigation and vice versa is considered, for at least the past 30 years, as the best strategy to answer questions in cultural heritage. Many archaeological queries have merged archaeological and scientific studies and have been carried out with a multidisciplinary approach that uses complementary analytical techniques. Here, we focused our efforts on outlining the strong relevance of elemental composition in chemistry and mineralogical investigations to answer important archaeological questions in the case of Apulian red figure pottery. This ceramic class is the most important quantitative handcraft production group of figured pottery in Magna Grecia and the most widespread and commercialized production from the third quarter of the fifth century to the end of the next century. The results obtained indicate that, by exploring chemical elements in the ceramic mixture, it is possible to extract information about provenance, manufacturing processes, originality and restoration techniques

A nonlinear principal component analysis to study archeometric data

Statistical techniques, when applied to data obtained by chemical investigations on ancient artworks, are usually expected to recognize groups of objects to classify the archeological finds, to attribute the provenance of items compared with earlier investigated ones, or to determine whether an archaelogical attribution is possible or not. The statistical technique most frequently used in archeometry is the principal component analysis (PCA), because of its simplicity in theory and implementation. However, the application of PCA to archeometric data showed severe limitations because of its linear feature. Indeed, PCA is inadequate to classify data whose behavior describe a curve or a curved subspace of the original data space. As a consequence of it, an amount of information is lost because the multi-dimensional data space is compressed into a lower-dimensional subspace including principal components. The aim of this work is then to test a novel statistical technique for archeometry. We propose a nonlinear PCA method to extract maximum chemical information by plotting data on the smallest number of principal components and to answer archeological questions. The higher accuracy and effectiveness of nonlinear PCA approach with respect to standard PCA for the analysis of archeometric data are shown through the study of Apulian red figured pottery (fifth–fourth century BC) coming from some of the most relevant archeological sites of ancient Apulia (Monte Sannace (Gioia del Colle), Egnatia (Fasano), Canosa, Altamura, Conversano, and Arpi(Foggia)). Copyright © 2016 John Wiley & Sons, Ltd