Earthenware

Earthenware is glazed or unglazed nonvitreous pottery[2] that has normally been fired below 1200°C.[3] Porcelain, bone china and stoneware, all fired at high enough temperatures to vitrify, are the main other important types of pottery.

Earthenware comprises

most building bricks, nearly all European pottery up to the seventeenth century, most of the wares of Egypt, Persia and the near East; Greek, Roman and Mediterranean, and some of the Chinese; and the fine earthenware which forms the greater part of our tableware today.[4]

Pit fired earthenware dates back to as early as 29,000–25,000 BC,[5][6] and for millennia, only earthenware pottery was made, with stoneware gradually developing some 5,000 years ago, but then apparently disappearing for a few thousand years. Outside East Asia, porcelain was manufactured only from the 18th century AD, and then initially as an expensive luxury.

After it is fired, earthenware is opaque and non-vitreous,[7] soft and capable of being scratched with a knife.[4] The Combined Nomenclature of the European Communities describes it as being made of selected clays sometimes mixed with feldspars and varying amounts of other minerals, and white or light-colored (i.e., slightly greyish, cream, or ivory).[7]

Plate Buwayhid
Painted, incised and glazed earthenware. Dated 10th century, Iran. New York Metropolitan Museum of Art
Top Section of a Water Jug, late 12th-early 13th century
Top section of a water jug or habb. Earthenware. Late 12th-early 13th century Iraq or Syria. Brooklyn Museum.[1]

Characteristics

Generally, earthenware bodies exhibit higher plasticity than most whiteware[8] bodies and hence are easier to shape by RAM press, roller-head or potter's wheel than bone china or porcelain.[9][10]

Due to its porosity, earthenware, with a water absorption of 5-8%, must be glazed to be watertight.[11] Earthenware has lower mechanical strength than bone china, porcelain or stoneware, and consequently articles are commonly made in thicker cross-section, although they are still more easily chipped.[9]

Darker-colored terracotta earthenware, typically orange or red due to a comparatively high content of iron oxide, are widely used for flower pots, tiles and some decorative and oven ware.[4]

Production

Earthen Potter
Pottery using an electric rotor

A general body formulation for contemporary earthenware is 25% kaolin, 25% ball clay, 35% quartz and 15% feldspar.[9][12]

Red terracotta flowerpots
Terracotta flower pots with terracotta tiles in the background

Modern earthenware may be biscuit (or "bisque")[13][14] fired to temperatures between 1,000 to 1,150 °C (1,830 to 2,100 °F) and glost-fired[15] (or "glaze-fired")[4][16] to between 950 to 1,050 °C (1,740 to 1,920 °F), the usual practice in factories and some studio potteries. Some studio potters follow the reverse practice, with a low-temperature biscuit firing and a high-temperature glost firing. The firing schedule will be determined by the raw materials used and the desired characteristics of the finished ware.

Historically, such high temperatures were unattainable in most cultures and periods until modern times, though Chinese ceramics were far ahead of other cultures in this respect. Earthenware can be produced at firing temperatures as low as 600 °C (1,112 °F) and many clays will not fire successfully above about 1,000 °C (1,830 °F). Much historical pottery was fired somewhere around 800 °C (1,470 °F), giving a wide margin of error where there was no precise way of measuring temperature, and very variable conditions within the kiln.

After firing, most earthenware bodies will be colored white, buff or red. For red earthenware, the firing temperature affects the color of the clay body. Lower temperatures produce a typical red terracotta color; higher temperatures will make the clay brown or even black. Higher firing temperatures may cause earthenware to bloat.

Types of earthenware

Chinese - Pair of Sculptures - Women on Horseback - Walters 492329
Chinese earthenware tomb sculpture.[17] The Walters Art Museum.

There are several types of earthenware, including:

References

  1. ^ "Brooklyn Museum". www.brooklynmuseum.org. Archived from the original on 30 April 2018. Retrieved 30 April 2018.
  2. ^ ASTM C242 – 15. Standard Terminology Of Ceramic Whitewares And Related Products
  3. ^ "Art & Architecture Thesaurus Full Record Display (Getty Research)". www.getty.edu. Archived from the original on 22 December 2017. Retrieved 30 April 2018.
  4. ^ a b c d Dora Billington, The Technique of Pottery, London: B.T.Batsford, 1962
  5. ^ David W. Richerson; William Edward Lee (31 January 1992). Modern Ceramic Engineering: Properties, Processing, and Use in Design, Third Edition. CRC Press. ISBN 978-0-8247-8634-2.
  6. ^ Rice, Prudence M. (March 1999). "On the Origins of Pottery". Journal of Archaeological Method and Theory. 6 (1): 1–54. doi:10.1023/A:1022924709609.
  7. ^ a b Combined Nomenclature of the European Union Published by the EC Commission in Luxembourg, 1987
  8. ^ An industry term for ceramics including tableware and sanitary ware
  9. ^ a b c Whitewares: Testing and Quality Control. W.Ryan and C.Radford. Institute of Ceramics & Pergamon. 1987.
  10. ^ Pottery Science: Materials, Process And Products. Allen Dinsdale. Ellis Horwood. 1986.
  11. ^ Ceramics Glaze Technology. J. R. Taylor & A. C. Bull. Institute of Ceramics & Pergamon Press. 1986
  12. ^ Dictionary of Ceramics, 3rd edition. A. E. Dodd & D. Murfin. Maney Publishing. 1994.
  13. ^ Rich, Jack C. (1988). The Materials and Methods of Sculpture. Courier Dover Publications. p. 49. ISBN 9780486257426.
  14. ^ "Ceramic Arts Daily – Ten Basics of Firing Electric Kilns". ceramicartsdaily.org. 2012. Archived from the original on 8 May 2012. Retrieved 16 April 2012.
  15. ^ Norton, F.H. (1960). Ceramics an Illustrated Primer. Hanover House. pp. 74–79.
  16. ^ Frank and Janet Hamer, The Potter's Dictionary of Materials and Techniques
  17. ^ "Women on Horseback". The Walters Art Museum. Archived from the original on 2016-03-04.

Further reading

  • Rado, P. An Introduction to the Technology Of Pottery. 2nd edition. Pergamon Press, 1988.
  • Ryan W. and Radford, C. Whitewares: Production, Testing And Quality Control. Pergamon Press, 1987.
  • 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.
  • "Petersons": Peterson, Susan, Peterson, Jan, The Craft and Art of Clay: A Complete Potter's Handbook, 2003, Laurence King Publishing, ISBN 1856693546, 9781856693547, google books

External links

Cassoulet

Cassoulet (French pronunciation: ​[ka.su.lɛ], from Occitan caçolet [kasuˈlet]) is a rich, slow-cooked casserole containing meat (typically pork sausages, goose, duck and sometimes mutton), pork skin (couennes) and white beans (haricots blancs). The dish originated in the south of France. It is named after its traditional cooking vessel, the cassole, a deep, round, earthenware pot with slanting sides.The traditional homeland of cassoulet is the region once known as the province of Languedoc, especially the towns of Toulouse, Carcassonne, and Castelnaudary, that claims to be where the dish originated. The brotherhood of Cassoulet, "La Grande Confrérie du Cassoulet de Castelnaudary", has organized competitions and fairs about cassoulet every year since 1999.

Ceramic glaze

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. Glazing renders earthenware vessels suitable for holding liquids, sealing the inherent porosity of unglazed biscuit earthenware. It also gives a tougher surface. Glaze is also used on stoneware and porcelain. In addition to their functionality, 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.

Most pottery produced in recent centuries has been glazed, other than pieces in unglazed terracotta, biscuit porcelain or some other types. Tiles are almost always glazed on the surface face, and modern architectural terracotta is very often glazed. Glazed brick is also common. Domestic sanitary ware is invariably glazed, as are many ceramics used in industry, for example ceramic insulators for overhead power lines.

The most important groups of traditional glazes, named after their main ceramic fluxing agent, are:

Lead-glazed earthenware, is shiny and transparent after firing, which needs only about 800 °C (1,470 °F). It has been used for about 2,000 years around the Mediterranean, in Europe, and China. It includes sancai and Victorian majolica.

Tin-glazed pottery, which coats the ware with an opaque white glaze. Known in the Ancient Near East and then important in Islamic pottery, from which it passed to Europe. Includes faience, maiolica, majolica and Delftware.

Salt-glazed ware, mostly European stoneware. It uses ordinary salt.

Ash glaze, important in East Asia, simply made from wood or plant ash, which contains potash and lime.

Feldspathic glazes of porcelain.Modern materials technology has invented new vitreous glazes that do not fall into these traditional categories.

Delftware

Delftware or Delft pottery, also known as Delft Blue (Dutch: Delfts blauw), is a general term now used for Dutch tin-glazed earthenware, a form of faience. Most of it is blue and white pottery, and the city of Delft in the Netherlands was the major centre of production, but the term covers wares with other colours, and made elsewhere. It is also used for similar pottery that it influenced made in England, but this should be called English delftware to avoid confusion.

Delftware is one of the types of tin-glazed earthenware or faience in which a white glaze is applied, usually decorated with metal oxides, in particular the cobalt oxide that gives the usual blue, and can withstand high firing temperatures, allowing it to be applied under the glaze. It also forms part of the worldwide family of blue and white pottery, using variations of the plant-based decoration first developed in 14th century Chinese porcelain, and in great demand in Europe.

Delftware includes pottery objects of all descriptions such as plates, vases and other ornamental forms and tiles. The start of the style was around 1600, and the most highly-regarded period of production is about 1640–1740, but Delftware continues to be produced. In the 17th and 18th centuries Delftware was a major industry, exporting all over Europe.

Faience

Faience or faïence ( or ; French: [fajɑ̃s]) is the conventional name in English for fine tin-glazed pottery on a buff earthenware body. The name comes via French as a term for Italian maiolica from Faenza in northern Italy. The invention of a white pottery glaze suitable for painted decoration, by the addition of an oxide of tin to the slip of a lead glaze, was a major advance in the history of pottery. The invention seems to have been made in Iran or the Middle East before the ninth century. A kiln capable of producing temperatures exceeding 1,000 °C (1,830 °F) was required to achieve this result, the result of millennia of refined pottery-making traditions. The term is now used for a wide variety of pottery from several parts of the world, including many types of European painted wares, often produced as cheaper versions of porcelain styles.

Italian tin-glazed earthenware, at least the early forms, is called maiolica in English, Dutch wares are called Delftware, and their English equivalents English delftware, leaving "faience" as the normal term in English for French, German, Spanish, Portuguese wares and those of other countries not mentioned (it is also the usual French term, and fayence in German).

Technically, lead-glazed earthenware, such as the French sixteenth-century Saint-Porchaire ware, does not properly qualify as faience, but the distinction is not usually maintained. Semi-vitreous stoneware may be glazed like faience.

Garba (dance)

Garba (ગરબા in Gujarati) is a form of dance which originated in the state of Gujarat in India. The name is derived from the Sanskrit term Garbha ("womb") and Deep ("a small earthenware lamp"). Many traditional garbas are performed around centrally lit lamp or a picture or statue of the Goddess Shakti. The circular and spiral figures of garba have similarities to other spiritual dances, such as those of Sufi culture (garba being an earlier tradition). Traditionally, it is performed during the nine-day Hindu festival Navarātrī (Gujarati નવરાત્રી Nava = 9, rātrī = nights). Either the lamp (the Garba Deep) or an image of the Goddess, Durga (also called Amba) is placed in middle of concentric rings as an object of veneration.

Güveç

Güveç is the name of a variety of earthenware pots used in Turkish cuisine, and of a number of casserole/stew dishes that are cooked in them. The pot is wide medium-tall, can be glazed or unglazed, and the dish in it is cooked with little or no additional liquid.Güveç dishes can be made in any type of oven-proof pan, but clay or earthenware pots are preferred of the heady, earthy aroma they impart to the stew.

ISO 3103

ISO 3103 is a standard published by the International Organization for Standardization (commonly referred to as ISO), specifying a standardized method for brewing tea, possibly sampled by the standardized methods described in ISO 1839. It was originally laid down in 1980 as BS 6008:1980 by the British Standards Institution. It was produced by ISO Technical Committee 34 (Food products), Sub-Committee 8 (Tea).

The abstract states the following:

The method consists in extracting of soluble substances in dried tea leaf, contained in a porcelain or earthenware pot, by means of freshly boiling water, pouring of the liquor into a white porcelain or earthenware bowl, examination of the organoleptic properties of the infused leaf, and of the liquor with or without milk, or both.

This standard is not meant to define the proper method for brewing tea, but rather how to document the tea brewing procedure so sensory comparisons can be made. An example of such a test would be a taste-test to establish which blend of teas to choose for a particular brand or basic label in order to maintain a consistent tasting brewed drink from harvest to harvest.

A revised standard is currently under development as ISO/NP 3103.The work was the winner of the parodic Ig Nobel Prize for Literature in 1999.

Jōmon pottery

The Jōmon pottery (縄文土器, Jōmon doki) is a type of ancient earthenware pottery which was made during the Jōmon period in Japan. The term "Jōmon" (縄文) means "rope-patterned" in Japanese, describing the patterns that are pressed into the clay.

Lead-glazed earthenware

Lead-glazed earthenware is one of the traditional types of glazed earthenware, which coat the ceramic body and render it impervious to liquids, as terracotta itself is not. Plain lead glaze is shiny and transparent after firing. Coloured lead glazes are shiny and either translucent or opaque after firing. Three other traditional techniques are tin-glazed earthenware, which coats the ware with an opaque white glaze suited for colored designs, salt-glazed earthenware such as stoneware, and the feldspathic glazes of Asian porcelain. Modern materials technology has invented new vitreous glazes that do not fall into these traditional categories.

In lead glazes tints provided by impurities render greenish to brownish casts, with aesthetic possibilities that are not easily controlled in the kiln. The Romans used lead glazes for high-quality oil lamps and drinking cups. At the same time in China, green-glazed pottery dating back to the Han period (25–220 AD) gave rise eventually to the 'sancai' or three-color Tang Dynasty ceramics, where the white clay body was coated with a layer of lead glaze and fired at a temperature of 800 degrees C. Lead oxide was the principal flux in the glaze; polychrome effects were obtained by using as coloring agents copper (which turns green), iron (which turns brownish yellow), and less often manganese and cobalt (which turns blue).

Much of Roman technology was lost in the West, but coarse lead-glazed earthenwares were universal in medieval Europe and in Colonial America. In England, lead-glazed Stamford Ware was produced in Stamford, Lincolnshire as early as the ninth century. It was widely traded across Britain and the near continent. In Italy during the 15th century lead-glazed wares were improved by the incremental addition of tin oxides under the influence of Islamic wares imported through Sicily, giving rise to maiolica, which supplanted lead-glazed wares in all but the most rustic contexts. The French 16th-century Saint-Porchaire ware is lead-glazed earthenware; an early European attempt at rivalling Chinese porcelains, it does not properly qualify as faience, which is a refined tin-glazed earthenware. In 16th-century France Bernard Palissy refined lead-glazed earthenware to a high standard. Victorian majolica is predominantly lead-glazed earthenware, introduced by Mintons in the mid-19th century as a revival of "Palissy ware" which soon became known as 'majolica' not to be confused with Minton's rare tin-glaze product also named 'majolica' which is included in the genre 'Victorian Majolica'.

Lead-glazed earthenwares in Britain include the Toby jugs, such as those made in the late 18th century by Ralph Wood the Younger at Burslem, Staffordshire.

Maiolica

Maiolica, also called Majolica is Italian tin-glazed pottery dating from the Renaissance period. It is decorated in colours on a white background, sometimes depicting historical and mythical scenes, these works known as istoriato wares ("painted with stories"). By the late 15th century, several places, mainly small cities in northern and central Italy, were producing sophisticated pieces for a luxury market in Italy and beyond.

Onggi

Onggi (Korean: 옹기, 甕器) is Korean earthenware, which is extensively used as tableware, as well as storage containers in Korea. It includes both unglazed earthenware fired near 600 to 700°C and pottery with a dark brown glaze that burnt over 1100°C.The origin of onggi dates to around 4000 to 5000 BC. The two types of earthenware are a patternless earthenware which is called mumun and a black and red earthenware. The former, a patternless earthenware, was made with lumps of clay including much fine sand; however, the predecessor of Goryeo celadon and Joseon white porcelain, a black/red earthenware, was being made with only lumps of clay. The color of earthenware is determined by the iron contained in the clay and the way of burning the pottery. The present onggi shape dates from the Joseon era. Many records about onggi are found in Sejong Sillok Jiriji (Korean: 세종실록지리지, "King Sejong's Treatise on Geography"): "There are three kilns that make the yellow onggi in Chogye-gun and Jinju-mok, Gyeongsang Province".

Ribesalbes

Ribesalbes is a municipality located in the province of Castellón, Valencian Community, Spain.

In 1780s, Joseph Ferrer founded an earthenware factory in Ribesalbes.

Shelley Potteries

Shelley Potteries, situated in Staffordshire, was earlier known as Wileman & Co. which had also traded as The Foley Potteries. The first Shelley to join the company was Joseph Ball Shelley in 1862 and in 1896 his son Percy Shelley became the sole proprietor, after which it remained a Shelley family business until 1966 when it was taken over by Allied English Potteries. Its china and earthenware products were many and varied although the major output was table ware. In the late Victorian period the Art Nouveau style pottery and Intarsio ranges designed by art director Frederick Alfred Rhead were extremely popular but Shelley is probably best known for its fine bone china “Art Deco” ware of the inter-war years and post-war fashionable tea ware.

Wileman refers to a backstamped version of which predates Shelley-branded porcelain. The factory that manufactured this brand of porcelain was located in Longton, Staffordshire, England.

Spode

Spode is an English brand of pottery and homewares produced by the company of the same name, which is based in Stoke-on-Trent, England.

Spode was founded by Josiah Spode (1733–1797) in 1770, and was responsible for perfecting two extremely important techniques that were crucial to the worldwide success of the English pottery industry in the century to follow.

He perfected the technique for transfer printing in underglaze blue on fine earthenware in 1783–1784 – a development that led to the launch in 1816 of Spode's Blue Italian range, which has remained in production ever since. Josiah Spode is also often credited with developing, around 1790, the formula for fine bone china that was generally adopted by the industry. His son, Josiah Spode II, was certainly responsible for the successful marketing of English bone china.

Today, Spode is owned by Portmeirion Group, a pottery and homewares company based in Stoke-on-Trent. Many items in Spode's Blue Italian and Woodland ranges are made at Portmeirion Group's factory in Stoke-on-Trent.

Stoneware

Stoneware is a rather broad term for pottery or other ceramics fired at a relatively high temperature. A modern technical definition is a vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire clay. Whether vitrified or not, it is nonporous (does not soak up liquids); it may or may not be glazed. Historically, across the world, it has been developed after earthenware and before porcelain, and has often been used for high-quality as well as utilitarian wares.

As a rough guide, modern earthenwares are normally fired in a kiln at temperatures in the range of about 1,000°C (1,830 °F) to 1,200 °C (2,190 °F); stonewares at between about 1,100 °C (2,010 °F) to 1,300 °C (2,370 °F); and porcelains at between about 1,200 °C (2,190 °F) to 1,400 °C (2,550 °F). Historically, reaching high temperatures was a long-lasting challenge, and temperatures somewhat below these were used for a long time. Earthenware can be fired effectively as low as 600°C, achievable in primitive pit firing, but 800 °C (1,470 °F) to 1,100 °C (2,010 °F) was more typical. Stoneware also needs certain types of clays, more specific than those able to make earthenware, but can be made from a much wider range than porcelain.

Stoneware is not recognised as a category in traditional East Asian terminology, and much Asian stoneware, such as Chinese Ding ware for example, is counted as porcelain by local definitions. Terms such as "porcellaneous" or "near-porcelain" may be used in such cases. One definition of stoneware is from the Combined Nomenclature of the European Communities, a European industry standard. It states:

Stoneware, which, though dense, impermeable and hard enough to resist scratching by a steel point, differs from porcelain because it is more opaque, and normally only partially vitrified. It may be vitreous or semi-vitreous. It is usually coloured grey or brownish because of impurities in the clay used for its manufacture, and is normally glazed.In industrial ceramics, five basic categories of stoneware have been suggested:

Traditional stoneware – a dense and inexpensive body. It is opaque, can be of any colour and breaks with a conchoidal or stony fracture. Traditionally made of fine-grained secondary, plastic clays which can used to shape very large pieces.

Fine stoneware – made from more carefully selected, prepared, and blended raw materials. It is used to produce tableware and art ware.

Chemical stoneware – used in the chemical industry, and when resistance to chemical attack is needed. Purer raw materials are used than for other stoneware bodies. Ali Baba is a popular name for a large chemical stoneware jars of up to 5,000 litres capacity used to store acids.

Thermal shock resistant stoneware – has additions of certain materials to enhance the thermal shock resistance of the fired body.

Electrical stoneware – historically used for electrical insulators, although it has been replaced by electrical porcelain.

Tajine

A tajine or tagine (Moroccan Arabic طجين tažin, from Arabic: طاجن tājun; Tifinagh: ⵜⴰⵊⵉⵏ) is a Maghrebi dish which is named after the earthenware pot in which it is cooked. It is also called a Maraq/marqa in North Africa.

Terracotta

Terracotta, terra cotta or terra-cotta (pronounced [ˌtɛrraˈkɔtta]; Italian: "baked earth", from the Latin terra cocta), a type of earthenware, is a clay-based unglazed or glazed ceramic, where the fired body is porous. Terracotta is the term normally used for sculpture made in earthenware, and also for various utilitarian uses including vessels (notably flower pots), water and waste water pipes, roofing tiles, bricks, and surface embellishment in building construction. The term is also used to refer to the natural brownish orange color of most terracotta, which varies considerably.

This article covers the senses of terracotta as a medium in sculpture, as in the Terracotta Army and Greek terracotta figurines, and architectural decoration. Asian and European sculpture in porcelain is not covered. Glazed architectural terracotta and its unglazed version as exterior surfaces for buildings were used in Asia for some centuries before becoming popular in the West in the 19th century. Architectural terracotta can also refer to decorated ceramic elements such as antefixes and revetments, which made a large contribution to the appearance of temples and other buildings in the classical architecture of Europe, as well as in the Ancient Near East.

In archaeology and art history, "terracotta" is often used to describe objects such as figurines not made on a potter's wheel. Vessels and other objects that are or might be made on a wheel from the same material are called earthenware pottery; the choice of term depends on the type of object rather than the material or firing technique. Unglazed pieces, and those made for building construction and industry, are also more likely to be referred to as terracotta, whereas tableware and other vessels are called earthenware (though sometimes terracotta if unglazed), or by a more precise term such as faience.

Tin-glazed pottery

Tin-glazed pottery is earthenware covered in glaze containing tin oxide which is white, shiny and opaque (see tin-glazing for the chemistry); usually this provides a background for brightly painted decoration. It has been important in Islamic and European pottery, but very little used in East Asia. The pottery body is usually made of red or buff-colored earthenware and the white glaze imitated Chinese porcelain. The decoration on tin-glazed pottery is usually applied to the unfired glaze surface by brush with metallic oxides, commonly cobalt oxide, copper oxide, iron oxide, manganese dioxide and antimony oxide. The makers of Italian tin-glazed pottery from the late Renaissance blended oxides to produce detailed and realistic polychrome paintings.

The earliest tin-glazed pottery appears to have been made in Iraq in the 9th century, the oldest fragments having been excavated during the First World War from the palace of Samarra about fifty miles north of Baghdad. From there it spread to Egypt, Persia and Spain before reaching Italy in the Renaissance, Holland in the 16th century and England, France and other European countries shortly after.

The development of white, or near white, firing bodies in Europe from the late 18th century, such as creamware by Josiah Wedgwood, and icreasingly cheap European porcelain and Chinese export porcelain, reduced the demand for tin-glaze Delftware, faience and majolica.

The rise in the cost of tin oxide during the First World War led to its partial substitution by zirconium compounds in the glaze.

Yayoi pottery

Yayoi pottery (弥生土器 Yayoi doki) is earthenware pottery produced during the Yayoi period, an Iron Age era in the history of Japan, by an Island which was formerly native to Japan traditionally dated 300 BC to AD 300.

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