Creamware printers to Josiah Wedgwood by 1763, for example. By 1760 creamware was often enamelled for decoration, using a technique adopted from the early porcelain industry. This consisted of painting overglaze on the ware with pigments made from finely powdered coloured glass and then firing again to fuse the enamel to the ware. The varied enamel colours did not fuse at the same temperature so several firings were generally needed, adding to the expense. There were approximately 130 potteries in North Staffordshire during the 1750s, rising to around 150 by 1763 and employing up to 7,000 people – a large number
Jasperware "dipped" (or "Jasper dip") respectively. The undyed body was white when fired, sometimes with a yellowish tinge; cobalt was added to elements that were to stay white. Named after the mineral jasper for marketing reasons, the exact Wedgwood formula remains confidential, but analyses indicate that barium sulphate is a key ingredient. Wedgwood had introduced a different type of stoneware called black basalt a decade earlier. He had been researching a white stoneware for some time, creating a body called "waxen white jasper" by 1773-74. This tended to fail in firing, and was not as attractive as the final jasperware, and