Underglaze

Abstract: On Site Raman analyses were performed at the Musee national de Ceramique, Sevres, France, on selected rare items of the earliest known European hard-paste porcelains and stonewares, produced from ~1710 to ~1750 in the Meissen workshop (Saxony) founded by J.F. Bottger and E.W. von Tschirnhaus. Characteristic on-site Raman signatures have been obtained for white Sake bottles from ~1715, a green bowl, depicting a purple landscape and dated 27th August 1726, a middle of the 18th century produced figurine and coffee cups. In addition some artefacts (a red polished stoneware cup from ca. 1710-1715, a white ewer stopper from ~1725, a blue underglaze decorated flat stopper believed to have been manufactured after 1719, and decorated coffee cups) were analysed at the laboratory. Raman spectra identified different types of mullite-rich bodies, including calcium-rich and quartz-containing pastes. Different types of glazes and pigments (haematite, Naples yellow, cassiterite, lapis lazuli ...) have also been identified. The results are discussed in the light of previous chemical analyses and historical records. We propose characteristic parameters to discriminate between the different production technologies.

Abstract: A micro-Raman spectroscopic study of underglaze blue ceramic shards was undertaken. The shards in this study are of Ming, Meissen and unknown origins. The Ming samples were donated to the National Cultural History Museum in Pretoria by private collectors and were confirmed by the museum as originating from the Ming period (1368–1644) in China. The shards of unknown origin were also supplied by the Museum and were excavated at sites in and around the city of Pretoria, South Africa. The shard obtained from the Museum fur Angewandte Kunst, Frankfurt am Main, originated from Meissen, close to Dresden in Germany and dates from the late 19th century. The blue pigment on all the shards was probed by focussing through the glaze at the ceramic/glaze interface using the depth-profiling method. The blue pigment used for decoration in all samples that were studied has been identified as the spinel-structured cobalt blue or cobalt aluminium oxide (CoAl2O4) and was shown to be mixed with amorphous carbon in two of the unknown archaeological shards, presumably to obtain a darker shade of blue. The unknown shards are also shown to contain white anatase (TiO2) applied on the surfaces prior to application of the colour and glaze, thereby suggesting the use of a two-step technology for the unknown archaeological shards as opposed to a single-step technology used by the Ming manufacturers. These differences could be used to distinguish shards of Ming origin from others. The method of probing the blue pigment through the glaze proved very useful and can now be extended to the study of underglaze pigments on the large number of intact glazed ceramic artefacts in museums around the world for comparison with archaeological shard samples. Copyright © 2007 John Wiley & Sons, Ltd.

Abstract: range of vibrant underglaze colours. Initially produced as a substitute for imported Chinese blue-and-white porcelain, the generally accepted sequence for the de- velopment of Iznik pottery starts in about 1480 with ‘Abraham of Kutahya’ ware and continues through ‘Golden Horn’ and ‘Damascus’ wares to bole red ware, the production of which began in the 1550s and continued to the seventeenth century (Rogers and Ward 1988. 186-8). The decoration of the ‘Abraham of Kutahya’ and ‘Golden Horn’ wares is predominantly blue whereas that of the ‘Damascus‘ and bole red wares is polychrome. The extent to which these different types were made simultaneously has not yet been fully resolved. The ‘Abraham of Kutahya’ and ‘Golden Horn’ wares appear to have been produced at both Kutahya and Iznik. In contrast, the ‘Damascus’ and bole red wares appear to have been made exclusively at Iznik. In the Ottoman sources ‘Iznik pottery’ is used more as a trade name than a provenance. Therefore, it must be emphasised that in using the term, as well as the terms ‘Abraham