Robert Taggart Hall
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Robert Taggart Hall was owner and sometime-president of The Hall China Company in East Liverpool, Ohio. He is credited with having rediscovered the long-lost single-fire process, a ceramic technology in which a piece of ware is glazed and then fired in a kiln just once.
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[edit] The two-fire or double-fire process
Before Hall's rediscovery of the method, ceramics were fired, glazed, and then fired a second time. Because the ware and glaze expanded and contracted at microscopically different rates--depending on temperature and humidity fluctuations--ceramics were particularly vulnerable to crazing, the appearance of a network of fine, razor-thin cracks all over the glaze.
Single-firing meant that the ware and glaze were literally fused together as a single entity, thereby virtually eliminating the crazing problem. Beyond the fact that this ensured the lasting beauty of a piece of ware, single-firing also gave superior resistance to thermal shock, chipping and absorption of odors and stains.
[edit] History of the single-fire process
The single-fire process was first created by Chinese ceramists during the earliest decades of the Qing Dynasty (1644 - 1911). The Qing Dynasty is generally divided into three distinct periods: Kangxi (emperor from 1662-1722); Yongzheng (emperor from 1722-1736); and Qianglong (emperor from 1736-1796).
The peace and prosperity of the Qing dynasty precipitated a tremendous flowering of the arts. Qing emperors strongly supported Chinese artists, artisans and craftspeople. Sometime following the Qing dynasty, the single-fire method was eventually lost.
[edit] Rediscovery of the single-fire process
When Robert Taggart Hall took over the running of Hall China in 1904, he was determined to figure out the process. With the help of staff chemists and ceramic engineers, he experimented over a period of seven years. Finally, in 1911, Hall and his staff came up not only with a recipe for glaze which would work, but with the correct firing temperature as well.
[edit] Lead-free ware by accident
Inadvertently, Hall China became the first pottery in the world to produce ware which was completely lead-free. This was due not to particular health or environmental considerations, but to the fact that lead was an expensive ingredient which wouldn't survive the high firing temperatures required by the single-fire process.
[edit] External links
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