Tuesday, September 8, 2009

Scratch Blue

During long and strenuous cataloging sessions it is sometimes easy to lose sight of how important a single sherd or two of ceramic can really be. Take for instance scratch blue decorated white salt-glazed stoneware. We have cataloged several pieces of this stoneware, the one on the right being from Stratum 2 of Unit 54 in the Compton Field and the one on the right being from Stratum 1 of Unit 74 in the Jamieson Field.

The scratch blue technique consists of incising decorative lines on a white salt-glazed vessel, which are then filled with cobalt. Any excess cobalt is wiped away, resulting in fine blue lines. This type of design was typically used on plates, cups, teapots, and tea boxes. Common designs were linear or floral, but there was variation such as this plate decorated with a scratch blue lion, as seen on the left. Later scratch blue was debased, meaning that some of the excess cobalt was allowed to remain on the vessel, thus more closely matching German Westerwald Stoneware imports, seen below to the right. Our second piece of scratch blue more closely resembles this "debased" type

Image from If These Pots Could Talk by Ivor Hume.

Image courtesy of Jefferson Patterson Park & Museum.

So what makes these two small pieces important? Scratch blue designs were made during a short period in the 18th century, predominately from 1745-1800, following an even shorter period when the incised lines on white salt-glazed vessels were filled with brown iron-oxide rather than cobalt. This limited production of scratch blue vessels enables more accurate dating of a stratum as it places it within a particular time range. This ultimately aids us in placing a site within a broader context in relation to other archaeological sites in the surrounding area.


If These Pots Could Talk by Ivor Hume.
Artifacts of Colonial America by Ivor Hume.

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