Editing Pottery (section)

===Glazing===
{{Main|Ceramic glaze}}
[[File:Sèvres - Émaillage - insufflation 050.jpg|thumb|Spraying glaze onto a vase]]
Glaze is a glassy coating on pottery, and reasons to use it include decoration, ensuring the item is impermeable to liquids, and minimizing the adherence of pollutants.

Glaze may be applied by spraying, dipping, trailing or brushing on an aqueous suspension of the unfired glaze. The colour of a glaze after it has been fired may be significantly different from before firing. To prevent glazed wares sticking to [[kiln furniture]] during firing, either a small part of the object being fired (for example, the foot) is left unglazed or, alternatively, special refractory "''spurs''" are used as supports. These are removed and discarded after the firing.

Some specialised glazing techniques include:
* [[Salt glaze pottery|Salt-glazing]] – [[common salt]] is introduced to the kiln during the firing process. The high temperatures cause the salt to volatilise, depositing it on the surface of the ware to react with the body to form a sodium aluminosilicate glaze. In the 17th and 18th centuries, salt-glazing was used in the manufacture of domestic pottery. Now, except for use by some studio potters, the process is obsolete. The last large-scale application before its demise in the face of environmental clean air restrictions was in the production of salt-glazed [[Sanitary sewer|sewer-pipes]].<ref>"Clay Sewer Pipe Manufacture. Part II – The Effect Of Variable Alumina, Silica And Iron Oxide In Clays On Some Properties Of Salt Glazes." H.G. Schurecht. ''The Journal of the American Ceramic Society.'' Volume 6. Issue 6, pp. 717–29.</ref><ref>"Dictionary Of Ceramics." Arthur Dodd & David Murfin. 3rd edition. ''The Institute Of Minerals.'' 1994.</ref>[[File:Large jar, Sanage ware, Heian period, 9th century, ash glaze - Tokyo National Museum - DSC05227.JPG|thumb|Ash glazed jar from 9th century, Japan.]]
* [[Ash glaze|Ash glazing]] – ash from the combustion of plant matter has been used as the flux component of glazes. The source of the ash was generally the combustion waste from the fuelling of kilns although the potential of ash derived from arable crop wastes has been investigated.<ref>"Ash Glaze Research." C. Metcalfe. ''Ceramic Review'' No. 202. 2003. pp. 48–50.</ref> Ash glazes are of historical interest in the Far East although there are reports of small-scale use in other locations such as the [[Catawba Valley Pottery]] in the United States. They are now limited to small numbers of studio potters who value the unpredictability arising from the variable nature of the raw material.<ref>"Glaze From Wood Ashes And Their Colour Characteristics." Y-S. Han, B-H. Lee. ''Korean Ceramic Society'' 41. No. 2. 2004.</ref>