Glaze is a layer or coating of a vitreous substance which has been fired to fuse to a ceramic object to color, decorate, strengthen or waterproof it. Vitreous refers to a material in an Amorphous, Glassy state (in contrast to a Crystalline state [1]
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Use
Glazing is functionally important for earthenware vessels, which would otherwise be unsuitable for holding liquids due to porosity. Earthenware is a common Ceramic material which is used extensively for Pottery tableware and decorative objects Glaze is also used on functional and decorative stoneware and porcelain. Stoneware a Vitreous or semivitreous ceramic ware of fine texture made primarily from nonrefactory fire clay Porcelain is a Ceramic material made by heating raw materials generally including Clay in the form of Kaolin, in a Kiln to temperatures In addition to the functional aspect of glazes, aesthetic concerns include a variety of surface finishes, including degrees of gloss and matte, variegation and finished color. Glazes may also enhance an underlying design or texture which may be either the "natural" texture of the clay or an inscribed, carved or painted design. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and
Glaze is used on building materials. The Iron Pagoda, built in 1049 CE in Kaifeng, China, of glazed bricks is an example. The Iron Pagoda (鐵塔 of Youguo Temple (佑國寺 Kaifeng City Henan province is a Buddhist Chinese pagoda built in 1049 AD Kaifeng ( formerly known as Bianliang ( Bianjing ( Daliang ( or simply Liang ( is a Prefecture-level city in eastern China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National [2]
Process
Glaze may be applied by dry dusting a dry mixture over the surface of the clay body. Liquid glazes—suspensions of various powdered minerals, and metal oxides—can be applied by dipping pieces directly into the glaze, pouring the glaze over the piece, spraying it onto the piece with an airbrush or similar tool, with a brush, or with any tool that will achieve the desired effect. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element An airbrush is a small air-operated tool that sprays various media including Ink and Dye, but most often Paint by a process of Nebulization
To prevent the glazed article sticking to the kiln during firing either a small part of the item is left unglazed or special refractory supports, kiln spurs, are used as supports which are removed and discarded after the firing. Kilns are thermally insulated chambers or Ovens in which controlled temperature regimes are produced Kiln spurs are supports often in the shape of a Tripod, used to maintain the shape and separate pieces of Ceramic during the firing process Small marks left by these spurs can sometimes be visible on finished ware.
Decoration applied under the glaze on pottery is generally referred to as underglaze. Underglaze is a method of decorating Ceramic articles the decoration is applied to the surface before it is glazed Underglazes are applied to the surface of the pottery, which can be either raw, "greenware", or "bisque" fired (an initial firing of some articles before the glazing and re-firing). 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" porcelain famously produced in England, The Netherlands, China and Japan. For other uses see Blue and white "Blue and white wares" designate white Pottery and Porcelain decorated under Porcelain is a Ceramic material made by heating raw materials generally including Clay in the form of Kaolin, in a Kiln to temperatures Spode is an English manufacturer of Pottery and Porcelain, based in Stoke-on-Trent. Delftware, or Delft Pottery, denotes blue and white pottery made in and around Delft in the Netherlands and the tin-glazed Pottery Imari porcelain is the European collectors' name for Japanese porcelain wares made in the town of Arita, in the former Hizen Province, northwestern Kyūshū The striking blue color is achieved by using the powerful colorant cobalt in the form of either cobalt oxide or cobalt carbonate, both of which are still commonly used in glaze formulation today. A colourant or colorant is something added to something else to cause a change in Colour. Cobalt blue is a cool slightly desaturated blue Color, historically made using Cobalt salts
Decoration applied on top of a layer of glaze is referred to as overglaze. Is more usually called on-glaze and refers to The outer layer or coat of glaze on a piece of Ceramics Also a decoration usually enamel, 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 (i. Pottery is the Ceramic ware made by potters It also refers to a group of materials that includes Earthenware, Stoneware In a discussion of Material science, enamel (or vitreous enamel or porcelain enamel in U e. , gold leaf) over the glaze. Metal leaf is a thin foil used for decoration It is also called composition leaf or schlagmetal.
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.
History
Earliest vessels date back to 10,000 BC. Vessels with a pointed shape and incised rope patterns, similar to Siberian vessels of the period, were made by people from northern Japan. These vessels were unglazed.
During the Kofun period of Japan, high-fired, hard-bodied sue ware was decorated with greenish natural ash glazes. The is an era in the History of Japan from around 250 to 538 The word kofun is Japanese for the type of burial mounds dating from this era was a blue-gray form of high-fired Pottery which was produced in Japan and southern Korea during the Kofun, Nara, and Heian periods From 552 AD 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. The Tang Dynasty ( Middle Chinese: dhɑng (June 18 618&ndashJune 4 907 was an imperial dynasty of China preceded by the Sui Dynasty and followed by Natural ash glaze, however, was commonly used throughout the country.
In the thirteenth century, flower designs were painted with red, blue, green, yellow, and black overglazes. Overglazes became very popular because of the polished look they gave ceramics. Ceramics and ceramic art in the art world means artwork made out of clay bodies and fired to form a ceramic.
See also
Footnotes
- ^ Ching, Francis D. Pottery is the Ceramic ware made by potters It also refers to a group of materials that includes Earthenware, Stoneware Glaze defects are any flaws in the surface quality of a Ceramic glaze, its physical structure or its interaction with the clay body Porcelain is a Ceramic material made by heating raw materials generally including Clay in the form of Kaolin, in a Kiln to temperatures Swatow ware or Swatow is a common name for a group of mainly late Ming Dynasty export Porcelain from China intended for the South East Asian Ash glazes are types of high temperature glazes for Stoneware Pottery that include the ashes of trees shrubs plants or grasses within the glaze is a generic term for a family of pottery glazes. They tend to range in color from milky white to a light orange sometimes with charcoal grey spotting known as "carbon trap" Celadon is a term for Ceramics denoting both a type glaze, and a ware of a specific color also called celadon. K. (1995). A Visual Dictionary of Architecture. New York: John Wiley and Sons, p. 32. ISBN 0-471-82451-3.
- ^ Daiheng, Gao (2002). Chinese Architecture -- The Lia, Song, Xi Xia, and Jin Dynasties, English Ed. , Yale University Press, p. 166, 183. ISBN 0-300-09559-7.
References
- 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.
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