AMALGAM TINNING OF CHINESE BRONZE ANTIQUITIES*

This paper investigates the question whether or not amalgam tinning was used for the plating of bronze objects in pre‐Han and Han dynasty China. The relevant literary sources are reviewed and amalgam tinning is characterized experimentally with regard to its micro‐structure and residual mercury content using metallography and electron microprobe analysis. Examination of a tinning sample from a Warring States dagger previously assumed to be amalgam tinned demonstrates that this was probably not the case, but that a trace of mercury found in the plating is likely to be the result of contamination.     

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.     

LEAD ISOTOPIC ANALYSIS OF EIGHTEENTH‐DYNASTY EGYPTIAN EYEPAINTS AND LEAD ANTIMONATE COLOURANTS*

New lead isotopic analyses are presented for lead antimonate coloured glass and faience from Amarna in Middle Egypt and dated to around 1350 BC. When compared to existing data, these suggest that Gebel Zeit on the Red Sea coast of Egypt may be the source for some of the lead antimonate colourants used in Egypt and possibly for the galena kohls of Eighteenth‐Dynasty date as well.     

ELECTRON SPIN RESONANCE STUDY OF PAPER SAMPLES DATING FROM THE FIFTEENTH TO THE EIGHTEENTH CENTURY

Electron paramagnetic resonance spectroscopy is used to detect paramagnetic impurities in differently degraded antique sheets of unprinted paper. Impurities consist primarily of transition metal ions (Fe³⁺, Mn²⁺, Cu²⁺) present in different environments and symmetries. Organic radicals, common in modern, wood pulp paper, are absent in these antique samples made from rags. Fe³⁺ is the largest impurity (from 300 to 700 ppm). Mn²⁺ is also present but its concentration does not exceed 50ppm. Cu²⁺ has been detected in about one-third of the samples. Coupled with nuclear magnetic resonance data, these results describe degradation as an hydrolytic process leading to a net increase of amorphous cellulose and to a decrease of bound water. Copper and rhombic iron appear to act as efficient degradation catalysts, whereas the presence of octahedral iron is almost irrelevant.     

A BRONZE SCULPTURE ATTRIBUTED TO LOUIS-SIMON BOIZOT AND PLATINUM COATING METHODS

During the examination of the sculpture of Medea Rejuvenating Aeson attributed to Louis-Simon Boizot (1743–1809), X-ray fluorescence analysis revealed, surprisingly, that the outer surface of the brass cast was patinated with platinum. Research into the history of platinum coating methods revealed that chemical techniques for the deposition of platinum from solution were in use before the advent of electroplating. Some experimental work to replicate the patination technique of electrochemical replacement plating of platinum based on recipes from the nineteenth century is described. The technical evidence suggests that a late eighteenth-century date for the sculpture is reasonable.     

ON SOME PHYSICAL CHARACTERISTICS OF CHINESE AND EUROPEAN RED WARES

When in the seventeenth and eighteenth century Chinese red ware from Yixing was imported into Europe, imitations of that ware, some of them delusively similar to the originals, were made in the Netherlands, Saxony, and England. With non-destructive energy dispersive X-ray fluorescence analysis (ED-XFA) the Chinese and different European red wares can be easily separated by comparing the patterns of their calcium oxide, manganese oxide, and lead contents. They also have density characteristics of their own.     

ESTIMATION OF THE BULK COMPOSITION OF FINE-GRAINED MEDIA FROM MICROCHEMICAL AND BACKSCATTER-IMAGE ANALYSIS: APPLICATION TO BISCUIT WASTERS FROM THE BOW FACTORY SITE,LONDON*

Microprobe and digitized electron-backscatter image data reveal that eighteenth-century Bow porcelain consists of a silica polymorph(s) (25–43 vol. %), a calcium phosphate phase (42–55%) with homogeneous and stippled textural variants, and a silicon-, aluminium-, and calcium-rich, former melt phase represented by discrete domains (14–20%) and micron-scale blebs that occupy 20–70% of the stippled calcium phosphate. Bulk compositions calculated from these data are deficient in calcium phosphate components and more siliceous than those determined by microprobe analysis of fused powders of the same samples. This reflects difficulties in determining representative values for the composition and volume of the melt phase, and underscores the limitations of the method where applied to media containing compositionally- or texturally-heterogeneous phases.     

Compositional and Microstructural Study of KoryŎ Celadon and Whiteware Excavated from SŎRi Kiln in Kyŏnggi Province

An extensive study of the composition and microstructure of celadon and whiteware sherds excavated at Sori, one of the most important sites that were active during the founding stage of the stoneware and porcelain industry in Korea, was carried out. The analysed sherds were organized according to four different levels of the excavation and four different styles of haemurigup foot rim. Principal component analysis of the chemical compositions of the sherds revealed slight differences in their body and glaze compositions between the levels of excavation. Porcelain stone with high silica and low aluminium contents was generally used as the body material and wood ash as the chief flux in the glaze. Over the period of operation, the aluminium content in the bodies of the ceramics decreased and the P₂O₅ content in the glazes increased. Glazed bodies were fired in a single step, in contrast to the two‐step method used in later ceramic production. Firing conditions were adjusted to produce vitrification of the glazes, which meant that vitrification of the ceramic bodies occurred to varying extents, mostly determined by the relative contents of flux in the body and the glaze.     

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.