World Library  
Flag as Inappropriate
Email this Article

Ceramic glaze

Article Id: WHEBN0006717182
Reproduction Date:

Title: Ceramic glaze  
Author: World Heritage Encyclopedia
Language: English
Subject: Pottery, Lead glass, Delftware, Earthenware, Onggi
Collection: Artistic Techniques, Ceramic Engineering, Ceramic Glazes, Glass Applications, Glass Compositions, Painting Techniques, Pottery
Publisher: World Heritage Encyclopedia

Ceramic glaze

Composite body, painted, and glazed bottle. Iran , 16th century (Metropolitan Museum of Art)

Ceramic glaze is an impervious layer or coating of a vitreous substance which has been fused to a ceramic body through firing. Glaze can serve to color, decorate or waterproof an item.[1]


  • Use 1
  • Composition 2
  • Process 3
  • History 4
  • Gallery 5
  • See also 6
  • Footnotes 7
  • References 8


Glazing renders earthenware vessels suitable for holding liquids, sealing the inherent porosity of terracotta. Glaze is also used on stoneware and porcelain. In addition to their functional aspect, glazes can form a variety of surface finishes, including degrees of glossy or matte finish and color. Glazes may also enhance the underlying design or texture either unmodified or inscribed, carved or painted.

Glaze is used to weatherproof brick or tile building materials. The Iron Pagoda, built in 1049 in Kaifeng, China, of glazed bricks is an example.[2]


Raw materials of ceramic glazes generally include silica, which will be the main glass former. Various metal oxides, such as sodium, potassium and calcium, act as a flux to lower the melting temperature. Alumina, often derived from clay, stiffens the molten glaze to prevent it from running off the piece. Colorants, such as iron oxide, copper carbonate or cobalt carbonate, and sometimes opacifiers such as tin oxide or zirconium oxide, are used to modify the visual appearance of the fired glaze. Glaze for lead-glazed earthenware is transparent and glossy after firing.


Islamic pottery tiles

Glaze may be applied by dry-dusting a dry mixture over the surface of the clay body or by inserting salt or soda into the kiln at high temperatures to create an atmosphere rich in sodium vapor that interacts with the aluminium and silica oxides in the body to form and deposit glass, producing what is known as salt glaze pottery. Most commonly, glazes in aqueous suspension of various powdered minerals and metal oxides are applied by dipping pieces directly into the glaze. Other techniques include pouring the glaze over the piece, spraying it onto the piece with an airbrush or similar tool, or applying it directly with a brush or other tool.

To prevent the glazed article from sticking to the kiln during firing either a small part of the item is left unglazed, or supported on small refractory supports called kiln spurs which are removed and discarded after the firing. Small marks left by these spurs are sometimes visible on finished ware.

Decoration applied under the glaze on pottery is generally referred to as underglaze. Underglazes are applied to the surface of the pottery, which can be either raw, "greenware", or "biscuit"-fired (an initial firing of some articles before the glazing and re-firing).[3][4][5] A wet glaze—usually transparent—is applied over the decoration. The pigment fuses with the glaze, and appears to be underneath a layer of clear glaze. An example of underglaze decoration is the well-known "blue and white" porcelain famously produced in England, the Netherlands, China and Japan. The striking blue color is achieved by using cobalt in the form of either cobalt oxide or cobalt carbonate, both of which are still commonly used.[6]

Decoration applied on top of a layer of glaze is referred to as overglaze. Overglaze methods include applying one or more layers or coats of glaze on a piece of pottery or by applying a non-glaze substance such as enamel or metals (e.g., gold leaf) over the glaze.

Overglaze colors are low-temperature glazes that give ceramics a more decorative, glassy look. A piece is fired first, overglaze is applied, and it is fired again. Once the piece is fired and comes out of the kiln, its texture becomes smoother because of the glaze.


Sancai ceramics of the Tang Dynasty

During the Kofun period of Japan, Sue ware was decorated with greenish natural ash glazes. From 552 to 794 AD, differently colored glazes were introduced. The three colored glazes of the Tang Dynasty were frequently used for a period, but were gradually phased out; the precise colors and compositions of the glazes have not been recovered. Natural ash glaze, however, was commonly used throughout the country.

In the 13th century, flower designs were painted with red, blue, green, yellow and black overglazes. Overglazes became very popular because of the particular look they gave ceramics.

From the eighth century, the use of glazed ceramics was prevalent in Islamic art and Islamic pottery, usually in the form of elaborate pottery.[7] Tin-opacified glazing was one of the earliest new technologies developed by the Islamic potters. The first Islamic opaque glazes can be found as blue-painted ware in Basra, dating to around the 8th century. Another significant contribution was the development of stoneware, originating from 9th century Iraq.[8] Other centers for innovative ceramic pottery in the Islamic world included Fustat (from 975 to 1075), Damascus (from 1100 to around 1600) and Tabriz (from 1470 to 1550).[9]


See also


  1. ^ Ching, Francis D.K. (1995). A Visual Dictionary of Architecture. New York: John Wiley and Sons. p. 32.  
  2. ^ Daiheng, Gao (2002). Chinese Architecture -- The Lia, Song, Xi Xia and Jin Dynasties (English ed.). Yale University Press. pp. 166, 183.  
  3. ^ “Cleaning Biscuit Fired Ceramic Ware” Hulse D.K, Barnett W.C. UK Pat.Appl.GB2287643A
  4. ^ “Investigation Into Bloating Behaviour Of Bone China Body During Biscuit Firing” Kara A. Euro Ceramics VIII Part.2 Trans. Tech. Publications, Switzerland. 2004. Pg.1717-1720
  5. ^ “Roller Kilns For The Fast Biscuit And Glost Firing Of Porcelain” Rodriguez Mamolar M.J., De La Fuente Revuelta J. Ceram. Inf.(Spain) 20, No.202. 1994. Pg. 25-27
  6. ^ ‘Ceramics Glaze Technology.’ J.R.Taylor & A.C.Bull. The Institute Of Ceramics & Pergamon Press. Oxford. 1986
  7. ^ Mason (1995), p. 1
  8. ^ Mason (1995), p. 5
  9. ^ Mason (1995), p. 7


  • Hamer, Frank and Janet. The Potter's Dictionary of Materials and Techniques. A & C Black Publishers, Limited, London, England, Third Edition 1991. ISBN 0-8122-3112-0.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.