Chemical analysis of white porcelains from the Ding Kiln site, Hebei Province, China

The Ding kilns were some of the most famous early kilns of medieval China, producing huge quantities of white and cream-white porcelains of outstanding technical and aesthetic quality. Since 1949 they have been excavated three times, in 1965, in 1987, and in 2009 respectively. In this latest study 69 white porcelain sherds from assured contexts and from the 2009 excavations were analyzed using laser ablation techniques (ICP-AES). The samples date from Five Dynasties, Northern Song and Jin Dynasties respectively (early 10th to early 13th C CE). The results show that Ding wares of different times show different characteristics that can be demonstrated through chemical composition. During the early phase of production the Ding ware bodies consisted largely of high firing kaolinitic clays with predominantly calcareous materials as fluxes. After the early Northern Song Dynasty, some calcareous material was replaced by a more potassic material. The compositions of the glazes show a parallel evolution to the bodies. However, because the glazes are very low in titania it seems unlikely that the main clay ingredients of the bodies could have been used in the glaze recipes. For much of the kiln site’s history the glazes appear to have been made mainly from the same siliceous flux-rich materials that had been blended with the main body-clays used to make the Ding ware porcelains, plus some extra calcareous material. The P2O5 contents of the glazes suggest that wood ash may have been one source of CaO in the glaze recipes.