Tin-glazing is the process of giving tin-glazed pottery items a ceramic glaze that is white, glossy and opaque, which is normally applied to red or buff earthenware. Tin-glaze is plain lead glaze with a small amount of tin oxide added.[1] The opacity and whiteness of tin glaze encourage its frequent decoration. Historically this has mostly been done before the single firing, when the colours blend into the glaze, but since the 17th century also using overglaze enamels, with a light second firing, allowing a wider range of colours.[2] Majolica, maiolica, delftware and faience are among the terms used for common types of tin-glazed pottery.
An alternative is lead-glazing, where the basic glaze is transparent; some types of pottery use both.[3] However, when pieces are glazed only with lead, the glaze becomes fluid during firing, and may run or pool. Colours painted on the glaze may also run or blur. Tin-glazing avoids these problems.[4]
The technique originated in the Near East and reached Europe during the late Middle Ages, with a peak in Italian Renaissance maiolica.[5] It was never used in East Asian ceramics. Tin oxide is still valued in glazes as both an opacifier and as a white colorant.[6] Tin oxide has long been used to produce a white, opaque and glossy glaze.[7][8] As well as an opacifying agent, tin oxide also finds use as a colour stabiliser in some pigments and glazes.[8] Minor quantities are also used in the conducting phases in some electrical porcelain glazes.[8][9]
- ^ Caiger-Smith, Alan, Tin-Glaze Pottery in Europe and the Islamic World: The Tradition of 1000 Years in Maiolica, Faience and Delftware, London, Faber and Faber, 1973 ISBN 0-571-09349-3
- ^ Lane, 1-2
- ^ For example polychrome Delftware; Savage, 160
- ^ Lane, 1
- ^ Lane, 3
- ^ ’The Glazer’s Book’ – 2nd edition. A.B.Searle.The Technical Press Limited. London. 1935.
- ^ ’Ceramic Glazes’ Third edition. C.W.Parmelee & C.G.Harman. Cahners Books, Boston, Massachusetts. 1973.
- ^ a b c ‘Ceramics Glaze Technology.’ J.R.Taylor & A.C.Bull. The Institute Of Ceramics & Pergamon Press. Oxford. 1986.
- ^ 'Conducting Glazes Part 2 : The Use of Valency Controlled Semiconducting Oxides and the Development of Tin Oxide Glazes'. D.B.Binns. British Ceramic Research Association RP652. 1973.