by Haley Hoffman – Archaeological Intern
Porcelain is a fairly common fine ceramic type composed of white ball clay and fired at temperatures above 1300°C (2372°F). The paste, or body, is highly compacted and ranges in color from white to greyish blue depending on where and how it is produced. Porcelain originated in China during the sixth and seventh centuries but was not available to the West until the sixteenth and seventeenth centuries through Portuguese and Dutch trade. There are two main types of Porcelain, hard paste and soft paste. It can be difficult to differentiate between some hard and soft paste porcelains.
Hard paste porcelain was originally made by the Chinese and is composed of ball clay and a finely ground feldspartic rock, petuntse. Chinese export hard paste porcelain typically has a blue to grey tint. The paste is highly compact due to high firing temperatures for long periods of time and follows a conchoidal fracture pattern similar to other fine grained materials. The glaze is usually fused to the paste. Many describe the glaze as nearly indistinguishable from the paste.
Soft paste porcelain is composed of a variety of different clays in addition to other ingredients like salt and soapstone. Eighteenth century English soft paste porcelain typically has a whiter body with a glaze that is distinguishable from the paste. The glaze was also made of a variety of different compounds and was a semi-gloss that is often distinct from the body of the ceramic. The paste is less compact, or softer, than hard paste porcelain.
One of the most commonly used porcelain decorative techniques for both Chinese export and English production were blue underglazed painted designs. Typical motifs depicted in this technique included animals, floral design, people, architecture and repetitive patterns. Willow Ware was an extremely popular blue underglaze pattern. The design has a characteristic geometric pattern around the rim and a themed landscape picture in the center.
Porcelain’s popularity, copies and reproductions of previous styles have been produced for centuries, can make dating extremely difficult. Regardless of this setback, scholars are working to identify small distinctions in marks and motifs in designs to help identify them. George Miller is one such scholar who in 2002 published an article on the subject titled, Telling Time for Archaeologist.
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1991 Porcelain. Miller’s Publications, June.
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