Saturday, November 17, 2007

German Salt Glaze

Germany: Salt-Glaze: Rhineland early centre of Roman occupation, pottery traditions. Large scale production by 7th c.; kiln improvements in 9th made for tougher wares. Stoneware (steinzeug) produced between 1000-1200 CE—first in Europe (China: 500 BCE). Area favoured with wood supply, stoneware clays, river transport, population base, bronze-working traditions. Developments relate to brewing industry—introduce hops c. 1500—big upsurge in beer consumption requires hygienic, sturdy wares. Canette--in Germany, short fat pint; Schnelle: ("fast")--tall, tapering mug; Bellarmines (face modelled on neck—satirize Cardinal opposed to drinking).
By the sixteenth century workshops in Siegburg, Raren, Cologne and elsewhere were producing highly artistic wares applied with moulded decoration of mythological and biblical scenes, often based on contemporary engravings, or naturalistic foliate ornament, political images and armorial devices. Siegburg was renowned for the production of an almost white stoneware with delicately modelled relief decoration in the Renaissance style. Merchants from Cologne were granted licence from 1570 to transport and sell Siegburg stoneware to merchants in Hamburg.
Salt glaze--at stoneware temperatures (1100-1200C), salt added to kiln decomposes to form sodium oxide and hydrogen chloride—released as (noxious) gas—sodium fluxes with silica and aluminum in pot surface, forms tough, thin, shiny glaze--colour based on reduction/oxidization and iron content of clay. Salt firings on this scale environmentally bad: chlorine gases unhealthy. (note: many contemporary studio potters use salt glaze, but on a much smaller scale, in which case the environmental effects are less concerning.) Salt glaze likely produced by 1400s, but first dated ware 1539. Control by trade unions, foreigners only for menial tasks, limit supply.
Defining characteristics of Salt Glaze: use of molds; originals cut in fine sandstone, impressions taken in pipe clay--double negative (to protect original mold)--crisp, detailed. Clay mined from shafts, salt imported from Low Countries (used to salt Newfoundland cod). Wares wheel-thrown, profiles crisped up with templates, bone tools. Colour added—"scratch blue" cobalt frit (smalt) rubbed into incised lines. Production of wares stimulated by improvements in beer (addition of hops). Potteries disrupted by Thirty years war (1618-48), relocate. Main centres: Seigburg—throw marks, pie crust foot, elaborate modelled friezes based on engravings, developing print culture, white-burning clays. Raeren brown salt-glaze imitated bronze, often friezes modelled, pious inscriptions around waists.
Jan Emens Mennicken active 1566-1594--best-known-classical scenes, nudes, festival and religious scenes. Wares widely exported. Koln: early centre, dark chestnut pots—dispute with potters; they move to Freschen. Kannenbacherland--land of potters--in Westerwald where potters fled to avoid war—produced Seigburg-style wares—grey or blue-grey, intricate engravings, pious sayings—eventually more geared towards colour (fashions change).
Kreussen (Bavaria): most elaborate, costly salt-glaze—inspired by/compete with maiolica, overglaze enamels—colourful, popular 1620-1750. Salt-glaze wore silverware down, eventually replaced by maiolica, creamwares in 18th c.

1 comment:

Phil said...

Please review your assertion that salt glazing is 'environmentally bad' in view of recent research. Ceramic Review No. 157 and Salt Glazing by Phil Rogers.