A TECHNOLOGICAL EXAMINATION OF NINTH–TENTH CENTURY AD ABBASID BLUE‐AND‐WHITE WARE FROM IRAQ,AND ITS COMPARISON WITH EIGHTH CENTURY AD CHINESE BLUE‐AND‐WHITE SANCAI WARE*

Eight sherds of ninth–tenth century ad Abbaesid blue‐and‐white glazed earthenware, excavated in 1931 at Hira in western Iraq, were analysed using, variously, quantitative wavelength‐dispersive spectrometry (WDS) and energy‐dispersive spectrometry (EDS) in association with scanning electron microscopes (SEM), and semi‐quantitative X‐ray fluorescence spectrometry (XRF). In order to compare the compositions of the cobalt pigments used, the glazes of seven complete vessels of eighth century ad Chinese Tang blue‐and‐white sancai were also analysed semi‐quantitatively using XRF. The Abbasid wares were shown to have used traditional Mesopotamian alkali–lime glazes applied to calcareous clay bodies. Half the glazes examined were opacified with tin oxide. Three types of blue decoration (i.e., raised; spreading; and flat, non‐spreading) were produced using a variety of formulations, including a mixture of cobalt pigment with lead oxide. The sources of the ores used for the cobalt pigments have not been identified. However, the analytical data showed that the cobalt ore used for the Abbasid blue‐and‐white ware could be distinguished from that used for the Tang blue‐and‐white sancai by its higher iron content and by the presence of a significant amount of zinc. The use of cobalt‐blue decoration on the ninth–tenth century ad Abbasid ware was anticipated in China by eighth century ad Tang blue‐and‐white sancai wares. However, whether its introduction by the Abbasid potters should be seen as an independent invention that followed the introduction of tin‐opacified glazes in Iraq, or whether it was influenced in some way by Chinese originals, is still unresolved.     

THE CHEMICAL COMPOSITION OF BLUE PIGMENT ON CHINESE BLUE‐AND‐WHITE PORCELAIN OF THE YUAN AND MING DYNASTIES (ad 1271–1644)*

The chemical compositions of the glazes and pigments of 39 blue‐and‐white porcelains of Ming Dynasty date and three of Yuan date were examined by SR‐XRF. Both the analysis of the Fe/Mn ratio in the light blue areas of the glaze and a comparison of the Fe/Mn values between light blue, dark blue and clear glaze areas reveals that the samples can be divided into three groups. The results indicate that there are two significant changes of provenance of blue pigment during the Ming Dynasty and that some kinds of pigment were most probably imported from the Middle East. Considering literature records and other scholars’ studies, an outline picture of the pigment used on Chinese blue‐and‐white porcelain produced in Jingdezhen in the Yuan and Ming Dynasties is presented.     

Evaluation of Quantitative XRF Analysis Applied to Determine Cobalt Sources in Chinese Blue‐and‐White Porcelain

A method using the ratios between MnO, Fe₂O₃ and CoO to differentiate the cobalt sources for Chinese blue‐and‐white porcelain was developed in Oxford in the 1950s using X‐ray fluorescence (XRF) analysis directly on the glaze. In this paper, six blue‐and‐white porcelain sherds from the Luomaqiao kiln were analysed by XRF on the glaze and by scanning electron microscopy with energy‐dispersive spectrometry (SEM‐EDS) in cross‐section. The ratios between MnO, Fe₂O₃ and CoO calculated by quantitative XRF and EDS analyses are different. The analysis depths for MnO, Fe₂O₃ and CoO are < 60 μm by XRF analysis. However, the average glaze thickness of samples is > 400 μm, and the MnO, Fe₂O₃ and CoO mainly remain in the lower layer of the glaze, which is beyond the analysis depths of XRF analysis. The limitations of major and minor quantitative analyses for differentiating cobalt sources are discussed.     

关于青花起源的思考

关于青花的起源,长期来一直有中国起源说和外来技术影响说两种意见。本文着重从低温釉陶生产技术源流和对青料的使用出发,论证了最早出现在巩县窑的唐青花瓷器,只是北魏以来低温釉陶生产技术在新条件下的新产物。认定唐青花的出现是外来绘画理论和绘画技术影响中国艺坛的结果。     

The Earliest High‐Fired Glazed Ceramic in China: Evidence from a Glazed Ceramic Sample from the Lajia Site,Qinghai Province

In the Majiayao cultural stratum of the Lajia site in Minhe County, Qinghai Province, much earthenware of rich variety and strong character has been found, among which the most special item is a suspected glazed white ceramic fragment. This study investigates this ceramic sherd and many other overfired objects. Energy‐dispersive X‐ray fluorescence spectroscopy, scanning electron microscopy – energy‐dispersive X‐ray spectroscopy, X‐ray diffraction and thermodilatometry were employed to analyse the composition, microstructure, phase composition and firing temperature of the white ceramic. In addition to large condensed glaze droplets, the white ceramic showed a thin and uneven glaze layer, which might represent the earliest results of the exploration of glaze‐making technology by Lajia inhabitants, and provide a new perspective on the study of the origin of Chinese proto‐porcelains.     

A Technological Study of the Elamite Polychrome Glazed Bricks at Susa,South‐Western Iran

This study investigated the technological features of the Neo‐Elamite glazed bricks discovered at the Acropolis of Susa, south‐western Iran, by conducting micro‐Raman spectroscopy, differential thermal analysis/thermogravimetry (DTA/TG), X‐ray diffraction (XRD) and scanning electron microscopy–energy‐dispersive X‐ray spectroscopy (SEM–EDS). The results showed that calcium antimonate white and lead antimonate yellow were used as opacifiers in the white, yellow and green glazes, and that green and turquoise glazes were achieved using copper. Coloured glazes were separated by a Si‐rich brown glaze to prevent them from running together during firing. The glazed bricks most probably were not fired at temperatures higher than 900°C.     

ON THE INFLUENCE OF DRYING AND FIRING OF CLAY ON THE FORMATION OF TRACE ELEMENT CONCENTRATION PROFILES WITHIN POTTERY*

On experimentally fired briquettes made of five chemically and mineralogically different clays, trace element concentration profiles from the centre to the surface of the briquettes have been measured by Neutron Activation in order to examine if drying and firing of the clays lead to a mobilization and subsequent migration of single components within a sherd. Mineralogical changes during firing have been determined by X‐ray diffraction. Generally, no such migration could be found. For two clays, arsenic was lost from the briquette during firing, forming non‐constant concentration profiles. If NaCl is present in the clay paste, sodium migrates towards the surface. Additionally, in the special case in which the presence of NaCl coincides with that of calcite, the heavier alkali elements evaporate, forming significant concentration profiles within the sherd.     

Comparison of the Different Types of Qinghua Porcelain from Jingdezhen in the Yuan Dynasty of China (ad 1271–1368) by Micro X‐ray Fluorescence Spectroscopy (μ‐XRF) and Microscopy

The Yuan Qinghua porcelain produced in the city of Jingdezhen, in China, mainly includes the gaudy blue type, a blue–grey or grey‐coloured type and the type featuring a blue colour with a slight amount of grey. For a long time, only the gaudy blue type was focused on and discussed, while the other two types, which contain equally important information with regard to recovering the manufacturing technology of Yuan Qinghua, were always ignored by scientific researchers. In this paper, by using micro X‐ray fluorescence spectroscopy (μ‐XRF), spectrophotometry and optical microscopy, all three different types of Yuan Qinghua porcelain are analysed systemically and, based on the analyses of the body, the glaze and the blue decoration, the differences in the materials and the manufacturing technologies of the three different types are discussed. This not only provides a good basis for the reconstruction of the whole picture of the manufacturing process of Yuan Qinghua porcelains in Jingdezhen, but also contributes to database‐building for the identification of Qinghua porcelain.     

The production and technology of glazed ceramics from the middle ages,found in the saepinum territory (Italy): a multimethodic approach*

A collection of ceramics from the Middle Ages found in Altilia and Terravecchia (the Saepinum area, Campobasso, Italy) were characterized by using different mineralogical analyses to investigate their provenance and production techniques. The body ceramic was investigated using Rietveld phase analysis of X‐ray powder diffraction patterns, X‐ray fluorescence spectrometry and scanning electron microscopy. The chemical compositions of the coatings were measured by scanning electron microscopy and their mineralogical compositions were determined using a particular technique of X‐ray small‐angle scattering (SAS) optimized for studies of thin films. Moreover, the material used for decoration was studied using micro‐Raman spectroscopy. The archaeometric results confirmed the distinction into two different ceramic classes, already individuated from archaeological analysis: the Altilia objects belong to the protomajolica class, whereas the objects from Terravecchia are RMR (ramina‐manganese‐red) ceramics. A comparison between the chemical and mineralogical compositions of good‐quality ceramic objects and those of waste products indicated local production of the ceramics. A sharp distinction was found in the chemical composition of the coatings: the Altilia products have tin‐opacified lead glazes, while the Terravecchia ones have transparent high‐lead glazes. Among the Altilia products, the unsuccessful process that produced a large quantity of discarded materials was attributed to the high lead content of the glazes. In fact, the principal advantage of the high lead content was to make the preparation and application of the glaze suspension easier, but the risk of reduction of lead oxide to metallic lead was greatly increased. Using micro‐Raman spectroscopy, the following minerals were identified as pigments: pyrolusite for the dark colour, malachite for green, lepidocrocite for yellow and hematite for red.     

CYPRIOT BYZANTINE GLAZED POTTERY: A STUDY OF THE PAPHOS WORKSHOPS

Twenty‐five samples of Byzantine glazed pottery from two archaeological sites between Limassol and Paphos region (Cyprus), dated between the 12th and 15th century ad were studied using micro X‐ray fluorescence spectroscopy, scanning electron microscopy and X‐ray diffraction analysis. It was found that all the glazes contain lead, following the main manufacturing process of medieval pottery in the Mediterranean territory, while some of them contain tin, possibly for better opacity. Furthermore, it is shown that copper, iron and cobalt with nickel are responsible for the decoration colours. Finally, the application of principal component analysis revealed significant differentiation for some of the samples.     

河南巩义窑、河北邢窑出土瓷器的原料来源研究——以北朝和隋唐时期出产的青瓷、白瓷为例

为探讨河南巩义窑、河北邢窑出土的不同时期青瓷、白瓷的原料来源,用显微观察、电子探针(EPMA)等手段,分析其原料来源及技术工艺进行分析,并探讨两窑之间的技术联系。分析可知,两窑在瓷釉、瓷胎的原料配置上存在差异:巩义窑瓷胎均使用当地高岭土一元配方,瓷釉中加入瓷胎原料为基体并加入高钙草木灰;邢窑瓷胎在使用当地高岭土的基础上加入长石类矿物原料,瓷釉中除瓷胎所使用的黏土以外,还加入含有高钙高镁的草木灰或矿物原料。两窑还存在一些共性如:两窑瓷釉均添加石英类原料以提高SiO_2含量;巩义窑与邢窑两地早期、唐中期产品形制相似,原料配方有共通之处,说明当时两地在陶瓷的原料配方、制瓷技术中有过交流。     

A STUDY OF ANCIENT CHINESE PORCELAIN WARES OF THE SONG‐YUAN DYNASTIES FROM CIZHOU AND DING KILNS WITH ENERGY DISPERSIVE X‐RAY FLUORESCENCE*

Multi‐variable statistical analysis based on energy dispersive X‐ray fluorescence measurements on both porcelain body and glaze is employed to give clear and consistent classification of porcelain sherds from northern China of different styles from the Song‐Yuan dynasties (Ding and Cizhou styles), and also from the Sui‐Tang dynasties (Xing style). However, the observed separation is less clear for Cizhou style sherds produced at neighbouring kiln sites. Imitation Ding porcelain samples produced by ancient Cizhou potters are also analysed.     

Studying the process of enamel powder preparation for émail champlevé by colour measurements and μ‐X‐ray mappings

Colour measurements and non‐destructive μ‐X‐ray mappings have been used for the first time in a comprehensive study of medieval émail champlevé works from different production areas in France and Germany. This approach has given a new insight into the enamel powder preparation process of the glass material used for enamelling. Colour measurements demonstrated that all production centres used glass of very similar hues, but with large differences in colour saturation. The μ‐X‐ray mapping results of blue enamels are described by a semi‐qualitative approach. Significant variations in oxide contents of lead, cobalt, manganese and antimony oxides were found. The variations suggest that more than one glass material was used to prepare the powder for enamelling. The variations in antimony and cobalt show that glass had different degrees of opacity and colour depth. The manganese and lead contents, which do not correlate with the cobalt or antimony contents, indicate that probably glass of different base compositions was used to prepare the enamel powder for one champlevé field.     

Composition of the Lustre Pigment Used in the Production Of 13th Century AD Raqqa Lustreware from Syria

The very rare find of the relic of the original lustre pigment attached to the glazed surface of a sherd of 13th century ad Raqqa type lustreware from Syria has been analysed using a combination of analytical scanning electron microscopy (SEM), micro‐X‐ray diffraction (XRD) and Rutherford backscattering spectroscopy (RBS). The composition of the pigment relic inferred from these analyses is shown to match those of recipes for lustre production given in the early treatises by Jazbir Ibn Hayyan (c. ad 721–c. ad 815) and Abū'l Qasim (ad 1301). Similarities and differences between this 13th century ad Syrian pigment and pigments used in the ninth century ad in Iraq, in the 14th century ad in Islamic and Hispano‐Moresque Spain, and in the 16th century ad in Renaissance Italy are discussed.     

LEAD ISOTOPE ANALYSIS OF TANG SANCAI POTTERY GLAZES FROM GONGYI KILN,HENAN PROVINCE AND HUANGBAO KILN,SHAANXI PROVINCE

Through the use of MC–ICP–MS, this study analyses the lead isotope ratios of 19 Tang Sancai pottery glazes unearthed from the Gongyi and Huangbao kiln sites. According to their different lead isotope ratios, the two kilns can be grouped separately. The research also suggests that the Gongyi and Huangbao kilns are independent production centres of Tang Sancai in the Tang Dynasty. The data from the Huangbao kiln indicates that the lead in the glazes originates from the Northern China geochemical province, while the data from Gongyi kiln suggests its source as the Yangtze geochemical province. Furthermore, the results obtained for the Tang Sancai pottery indicate that the lead sources for glaze making of these two kilns were very consistent, which suggests that lead isotope analysis could be a helpful method to identify the kilns producing Tang Sancai artefacts.     

中国钴着色材料的分类和来源

中国历史上的钴显色材料有颜料、玻璃、陶瓷釉。花绀青、钴蓝属历史颜料;钴显色蓝色玻璃可能始于西汉;钴显色蓝色陶瓷釉始于战国陶胎釉珠,唐朝唐三彩陶瓷釉发展成多个品种。钴显色材料有国产钴土矿类和进口Smalt类。原料矿中带入的锰、铁、镍、砷、铋等杂质对色彩有一定影响。     

The Tomb of the Three Brothers in Palmyra: The Use of Mimetite,A Rare Yellow Pigment,in A Rich Decoration

The wall paintings of the Tomb of the Three Brothers in Palmyra display a very rich Greco‐Roman iconography. The study of the painting reveals the use of a great variety of pigments, including Egyptian blue and an extremely rare bright yellow pigment, mimetite, of which no other traces are known for this period. This pigment was identified through the combined use of two methods of analysis, scanning electron microscopy associated with X‐ray microanalysis (SEM–EDS) and X‐ray micro‐diffraction (XRD). The varied chromatic palette used underlines the refinement and the particular care given to these decorations. Notable differences have been found between the pigments of the decorations of the arch and those used for the rest of the chamber.