Export Chinese blue-and-white porcelain: compositional analysis and sourcing using non-invasive portable XRF and reflectance spectroscopy

The chemical composition of Chinese blue-and-white porcelain, from the body to the pigment and the glaze, has been widely investigated over the last decades. However, most studies focused on ware from official kilns and much less attention has been given to folk kilns whose production was primarily aimed at supplying overseas markets. Moreover, scientific analysis has often relied on sophisticated laboratory-based instrumentation, a methodology that can be used neither for large sets of archaeological sherds nor in the field. The research presented here evaluates the applicability of non-invasive portable X-ray fluorescence (pXRF) and fiber optics reflectance spectroscopy (FORS) for the study of overseas Chinese blue-and-white porcelain manufactured in Jingdezhen and Zhangzhou, the main production centers during the late 16th to early 17th centuries. Results obtained on a limited number of sherds found in Indonesia and the Philippines show that concentration levels of some minor and trace elements, in particular zirconium and associated thorium, are sufficient to clearly distinguish Jingdezhen and Zhangzhou productions. The composition of the cobalt-based blue pigment was also easily identified with pXRF, highlighting the Fe-poor and Mn-rich compositional pattern in accordance with the local asbolite ores used during this time period. Furthermore, FORS provided additional information on tint and shade variations of the blue pigment. Consequently, pXRF combined with FORS represents an innovative and cost effective analytical approach to study the chemistry and provenance of Chinese blue-and-white porcelain, particularly in the field and/or for large archaeological sherd collections.