POTTERY AND PORCELAIN: TERMS EXPLAINED

For the benefit of Jonathan in the Shomron, who thinks that I have an undue fascination with crockery, the following text reposted; lifted and more or less redacted from a post written quite a while back.

It is informational, and not meant as narrative.


GLAZES AND FIRING

Jun glazes (鈞泑), Ding porcelain (定瓷), Ru ware (汝窯), Guan (官窯), Ge ware (哥窯) from Chekiang (浙江), Celadon (青磁), 建陽窯, or Ming Era (明代) blue-and white (青花瓷). Jing De Zhen (景德鎮).

Jun ware (鈞窯 'gwan yiu'): a distinct blue celadon-type with opalescence caused by variations in the kiln-temperature during a slow heating-up and gradual cooling-off period in the firing, allowing the glaze to remain viscous for a long time. As with Celadon, there is iron in the material, which gives the blueish hues, and often traces of copper which render purplish streaks.

Ding porcelain (定瓷 'deng chi'): Ivory or cream-hued products famous from the Tang Dynasty onwards.

Ru ware (汝窯 'yü yiu '): Beautiful pale blue crackly glaze with hue variations. The iron oxide in the glaze becomes greenish and blueish when fired in a reducing atmosphere. Ru wares vary from off-white to beautiful pale blues, with brownish crackling due to the different expansion rates of the body and the glaze.

[Iron oxide: 鐵氧化物 'tit yeung faa mat'.]

Guan ware (官窯 'gun yiu'): Thin-walled thick glazed porcelains made under court supervision from the Sung Dynasty, more particularly Southern Sung. The body is brown or greyish brown, the luminescent glaze itself a velvety enamelesque with bold crackles, in shades of white, off-yellow, faint greens, or pale pale blues.

Ge ware (哥窯 'go yiu'): Related to Guan ware, and developed during late Song - early Yuan. Jing De Zhen. Both crackled blueish-glazed ware and yellowish glaze with bold dark crackles interspersed with lighter reddish hairlines.

Celadon (青磁 'ching chi'): The famous greenish - blueish - yellow-brownish hue range is because of iron oxides, the reduction firing makes it crackly. This was most famously manufactured at the Long Guan kilns (Longguan: 龍泉 'lung chuen') in Zhejiang province (浙江 'chit kong'), which is south of Shanghai. It was also produced at Jingdezhen (景徳鎮 'king tak chan'), as well as in Korea and Japan. It is still made in all those places.

Blue and white wares (青花 'ching faa'): White porcelain with cobalt oxide decorative patterns sealed-in by a clear glaze. The blue pigment was usually somewhat impure, which added character and a glowing quality, especially with faint bleeding past the lines during firing.

[Cobalt oxide: 鈷氧化物 'gu yeung faa mat'.]

Rabbit's fur (兔毫 'tou hou'): Often called 'partridge pattern glaze' (鹧鸪斑釉 'je gu paan yau'), these are usually black or dark brown (黑釉 'hak yau') tea-bowls (茶碗 'chaa wun') from the Kienyang kiln (type: 建陽窯黑釉 'kin yeung yiu hak yau') created during the Sung Dynasty, with striations and streaks like partridge feathers (鹧鸪羽毛 'je gu yiu mou') caused by iron oxide "curdling" in the glaze during firing. Prized variations include greyish rabbit fur (灰兔毫 'fui tou hou'), yellow rabbit fur (黃兔毫 'wong tou hou'), silver rabbit fur (銀兔毫 'ngan tou hou'), and gold rabbit fur (金兔毫 'kam tou hou'). 

Oil-spot (油點瓷 'yau dim chi' or 天目釉 'tin muk chi'): Technically this is a variation of rabbit's fur in which the glaze is applied thickly, and as the red iron oxide molecules release oxygen they head to the surface, where the oxygen escapes and traces of iron are left, creating spots. Really thick glazes require a higher proportion of feldspar to stiffen so that they do not run and fuse the ceramic objects to the surfaces within the kiln on which they were placed. At extremely high temperatures, the glaze flows down, creating the rabbit fur effect; naturally these products will have a relatively thin glaze compared to oil-spot, and often the foot is tall and bare.

Imperial yellow, mustard yellow enamel (黄搪瓷 'wong tong chi'): In Chinese the various constituents are not differentiated, but you should know that so-called 'imperial yellow' is lead-antimonate -- three parts lead oxide, one part powdered quartz, plus oxides and binders -- fired at a lower temperature than porcelain glazes, and hence not safe for food service. But the result is beautiful, and vessels with an interior free of the enamel (in other words with a white porcelainous glaze) should be safe.
Often called 'soft yellow' (嬌黄 'giu wong').



See this post for additional explicata of the terms: Porcelain Lookup
Or this post for the material in a previous context: Canton Road



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