INCISED SLIPWARE PRODUCTION AT CASTELFIORENTINO (FLORENCE): THE ‘VIA BERTINI’ SITE (15TH–17TH CENTURIES)*

This study deals with the physical–chemical and mineralogical–petrographic investigations (OM, SEM–EDS, EPMA, ICP, XRpD, Mössbauer and IR) conducted on first‐ and second‐firing wasters belonging to two types of incised slipware (sgraffito), manufactured at Castelfiorentino between the late 15th and the early 17th centuries. Raw materials, colouring agents and firing products were analysed in order to establish the production technology of the ceramic coatings, by means of detailed microtextural and chemical investigations. The pottery underwent two firing processes: the firing of the white slip‐coated ceramic body and a further firing after application of the glaze. The homogeneity of the raw materials, white slip and glaze is remarkable, and demonstrates the use of well‐established recipes with a constant supply of raw materials from the same places. Highly efficient kiln management during both firings is revealed by body–glaze interface reactions.     

CHARACTERIZATION OF CORAL RED SLIPS ON GREEK ATTIC POTTERY*

Samples of red and black gloss from Greek Attic pottery of the late sixth to fifth centuries bc were examined using scanning electron microscopy (SEM and FIB/STEM). The focus of the study was the chemical and microstructural characterization of the red gloss that was first produced during this period. Two groupings of red gloss were revealed. One red was found to be compositionally similar to the black glosses (labelled ‘LCM coral red’). The other red showed more significant chemical differences, such as higher calcium and magnesium, in comparison to the black (labelled ‘HCM coral red’). The existence of two chemically distinct reds—otherwise identical in colour and texture—suggests that there was more than one source of clay available to the Attic potters for producing red.     

ARCHAEOMETRIC INVESTIGATIONS OF SGRAFFITO CERAMIC TILES (FIFTEENTH‐SIXTEENTH CENTURIES) RECOVERED FROM EXCAVATIONS IN UDINE (NORTH‐EAST ITALY)*

Most of the Renaissance sgraffito tiles excavated in Udine (Italy) constitute a homogeous group, the tile body having a CaO/MgO molar ratio ?= 3:2. They were produced using a dolomite‐ and calcite‐containing clay fired at 900–950°C. A small group of samples, with a lower firing temperature and a CaO/MgO ratio ?= 2:3, was probably produced in a different factory. Slip and transparent glaze, characterized by optical microscopy and inductively coupled plasma atomic emission spectrometry, are an illite‐rich clay and a lead silicate, respectively.     

NATURE AND MICROSTRUCTURE OF GALLIC IMITATIONS OF SIGILLATA SLIPS FROM THE LA GRAUFESENQUE WORKSHOP*

The red glaze (slip) that characterizes the Terra Sigillata potteries greatly contributed to their success during the Roman period. The colour of the slip can in fact be partially explained by the microstructure (crystalline phases, grain sizes) and the physico‐chemistry (composition) of the ceramics. However, the precise process and the diffusion of this technique are still not fully known. In particular, we do not know yet how the production of sigillata took place in the south of Gaul, and the role that was played by the production under Italian influence (pre‐sigillata) preceding the first local sigillata. In this work, a combination of transmission electron microscopy (TEM) and X‐ray synchrotron diffraction techniques was used to study the microstructure of pre‐sigillata slips from the main southern Gaul workshop (La Graufesenque), in order to compare their characteristics with those of high‐quality sigillata. These first results seem to indicate that the antique potters chose clays adapted to their firing conditions and to the type of coating that they wanted to make. These productions cannot be described as an initial phase for the later sigillata production and, rather, seem to correspond to the intention of developing a specific type of pottery only inspired by the famous Italian sigillata forms.     

A PRELIMINARY PETROGRAPHIC ANALYSIS OF CYPRIOT WHITE SLIP II WARE*

Samples of Late Bronze Age White Slip II ware from Cyprus were analysed using optical and scanning electron microscopy in conjunction with energy and wavelength dispersive analyse The slip has a novel granular nature and the coarser aggregates are impressed into the outer surface of the body, indicating that it was applied to a moist surface before the vessels were fired. It has a consistent mineral assemblage (Mg‐chlorite + illite‐smectite + sphene + anatase/rutile ± albite) which is very similar to that of hydrothermally altered zones associated with copper orebodies in the Troodos Massif which were mined in antiquity Our analysis suggests that the raw material for the slip was not found at the ground surface, because the alteration assemblage is unaffected by oxidation and copper carbonate or iron staining. It may, therefore, be a by‐product of sub‐surface ore extraction     

THE TECHNOLOGY OF ‘GLAZED’ RESERVED SLIP WARE—A FINE CERAMIC OF THE HARAPPAN PERIOD*

‘Glazed’ Reserved Slip Ware (RSW) is a high‐quality glossy bichrome pottery of the Indus Valley civilization, and dates to the mature Harappan period (c. 2600–1900 bc ). Scanning electron microscopy with energy‐dispersive X‐ray analysis indicates that the surface coat on RSW is composed of a pale grey vitrified clay slip, which overlies a black slip with significantly higher iron oxide. Hence the term ‘sintered’ Reserved Slip Ware is to be preferred. X‐ray diffraction analysis indicates that both the pale and black slips contain hercynite, mullite and quartz, but observation by scanning electron microscopy shows that the black slips contain higher amounts of coarser‐grained hercynite. The elemental data suggest that different clays were used to make the bodies and the slips. However, key element ratios are very close in associated black and pale slips. The grey slip may have been produced by elutriation of the fine, iron oxide‐rich clay that was used to prepare the black slip. The pale grey slip was laid over the black and removed by combing to produce a bichrome effect, which evoked semi‐precious materials such as agate. RSW was a specialist product that required significantly higher input skill and resources than the majority of Harappan clay‐based ceramics. It is a further example of the range of sophisticated Harappan ceramic wares, which included faience, fired steatite and stoneware.     

DECORATED ARCHAIC POTTERY FROM THE HERACLES SANCTUARY AT THEBES: A MATERIALS,TECHNOLOGY AND PROVENANCE STUDY*

Forty‐seven decorated samples of Archaic pottery excavated at a Heracles sanctuary (Thebes, Boeotia) were studied through a combined surface and body approach, using non‐destructive techniques. Most of the samples were archaeologically classified as Theban/Boeotian, others as Corinthian and a few as possibly Euboean. The techniques employed were optical microscopy and SEM–EDAX (micromorphology and compositional analysis of the surfaces) and XRF for the analysis of the ceramic body. The results provided information on the technological level of the collected pottery as well as on the relation of the chemistry and micromorphology of the pigments, aimed at assisting provenance studies.     

CHARACTERIZATION OF RED‐COLOURED SLIPS (ALMAGRA) ON ISLAMIC CERAMICS IN MUSLIM SPAIN*

Small objects found in Islamic (eleventh‐century) kilns excavated in Zaragoza (Spain) were studied to determine the nature of the red coating of almagra pottery. Ceramics with almagra decoration were completely coated with a glossy deep‐red layer, a slip, applied to the body before firing. Chemical and mineralogical studies were carried out, together with analysis of a surface treatment with organic compounds. The results of this study confirm that almagra ceramics were produced by means of a specific and elaborate process (slip preparation, firing and wax application), demonstrating the introduction of this slip into local production during the Islamic period.     

The Source Provenance of Bronze Age and Roman pottery from Cyprus

Archaeological interpretations of ancient economies have been strengthened by chemical analyses of ceramics, which provide the clearest evidence for economic activity, and comprise both the objects of exchange and its means. Pottery is often manufactured from local materials, but its compositional diversity typically prevents significant patterns of resource utilization from being identified. Centrally located and positioned on traditional shipping routes, Cyprus maintained ties with and supplied a variety of distinctive ceramic products to the major commercial centres in the eastern Mediterranean throughout Antiquity. We analysed two Cypriot .ne wares and a variety of utilitarian pottery, as well as samples of extant Cypriot clays to determine source provenance. These chemical analyses provide an objective indication of the origins of ancient (Bronze Age and Roman) ceramics manufactured on Cyprus. The distribution of the probable clay sources and the links between pottery style and the material environment also afford a perspective on the spatial organization of large‐scale pottery production on the island. Compositional analysis provides the means to assemble geographies of pottery production and to unravel the interregional system of exchange that operated in Antiquity, but the ability to accomplish these tasks is predicated on systematic analyses of ceramic products and raw materials that are found far beyond the bounds of individual archaeological sites.