Celadon; the color, the glaze and the history.
Celadon is a term used to describe ceramic objects glazed in the jade green celadon color or a type of transparent glaze. Jade celadon is also known as Greenware by specialists and this transparent glaze often has small cracks. Celadon characteristic glazes are now available in many colours to be used on all clay bodies, not just the traditional porcelain. AMACO supply 18 different colors, and we stock 10 of those celadons. Traditionally celadon glazes were produced in a small range of shades of colour, centred on olive-green and extending to greenish blues.
Celadon refers to one of the most highly-esteemed of China's porcelain traditions, of which number in the hundreds. Produced for more than two millennia in Zhejiang province, the quality of celadon reached its zenith with the Longquan kilns of the Song dynasty a thousand years ago. Many of these kilns have survived to the present in Longquan in Zhejiang province, and today still produce the finest celadon in the world, hand-made and -fired in the same laborious way, with hundreds of individual steps, as their ancestors have done for centuries.
The color of Celadon owes much to the raw materials—specifically, the presence of iron in the clay and of iron oxide, manganese oxide, and quartz particles in the glaze—as well as to the firing conditions inside the kiln. Temperatures were commonly around, or below, 1150ºC, and the level of oxygen within the kiln was dramatically reduced at some stage of the firing; this is known as a reducing, rather than an oxidizing, atmosphere.
A celadon glaze is quite a simple glaze, though difficult to get a particularly good one. The application of the glaze is important - it has to be quite thick to get the right effect. Celadon glazes are glossy, transparent, and great to add beautifully vivid accents to textured and carved surfaces. Pieces made more recently all have a mostly symmetrical shape, uniform color and and fairly well detailed inlay.
The difference between modern celadon of high quality, and that of lesser quality can be seen in the detail of the inlay or painting, and the uniformity and color of the glaze. Upon close inspection, the inlaid and painted portions of a lower quality piece will appear somewhat blurred and indistinct, while those of better quality will be clear in detail.