Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 °C (1,380 and 1,560 °F). The powder melts, flows, and then hardens to a smooth, durable vitreous coating. The word comes from the Latin vitreum, meaning "glass".
Enamel can be used on metal, glass, ceramics, stone, or any material that will withstand the fusing temperature. In technical terms fired enamelware is an integrated layered composite of glass and another material (or more glass). The term "enamel" is most often restricted to work on metal, which is the subject of this article. Essentially the same technique used with other bases is known by different terms: on glass as enamelled glass, or "painted glass", and on pottery it is called overglaze decoration, "overglaze enamels" or "enamelling". The craft is called "enamelling", the artists "enamellers" and the objects produced can be called "enamels".
Enamelling is an old and widely adopted technology, for most of its history mainly used in jewelry and decorative art. Since the 18th century, enamels have also been applied to many metal consumer objects, such as some cooking vessels, steel sinks, and cast-iron bathtubs. It has also been used on some appliances, such as dishwashers, laundry machines, and refrigerators, and on marker boards and signage.
The term "enamel" has also sometimes been applied to industrial materials other than vitreous enamel, such as enamel paint and the polymers coating enameled wire; these actually are very different in materials science terms.
The word enamel comes from the Old High German word smelzan (to smelt) via the Old French esmail,or from a Latin word smaltum, first found in a 9th-century Life of Leo IV . Used as a noun, "an enamel" is usually a small decorative object coated with enamel. "Enamelled" and "enamelling" are the preferred spellings in British English, while "enameled" and "enameling" are preferred in American English.
The earliest enamel all used the cloisonné technique, placing the enamel within small cells with gold walls. This had been used as a technique to hold pieces of stone and gems tightly in place since the 3rd millennium BC, for example in Mesopotamia, and then Egypt. Enamel seems likely to have developed as a cheaper method of achieving similar results.
The earliest undisputed objects known to use enamel are a group of Mycenaean rings from Cyprus, dated to the 13th century BC.Although Egyptian pieces, including jewellery from the Tomb of Tutankhamun of c. 1325 BC, are frequently described as using "enamel", many scholars doubt the glass paste was sufficiently melted to be properly so described, and use terms such as "glass-paste". It seems possible that in Egyptian conditions the melting point of the glass and gold were too close to make enamel a viable technique. Nonetheless, there appear to be a few actual examples of enamel, perhaps from the Third Intermediate Period of Egypt (beginning 1070 BC) on. But it remained rare in both Egypt and Greece.
The technique appears in the Kuban during the Scythian period, and was perhaps carried by the Sarmatians to the ancient Celts.Red enamel is used in 26 places on the Battersea Shield (c.350–50 BC), probably as an imitation of the red Mediterranean coral, which is used on the Witham Shield (400-300 BC). Pliny the Elder mentions the Celts' use of the technique on metal, which the Romans in his day hardly knew. The Staffordshire Moorlands Pan is a 2nd-century AD souvenir of Hadrian's Wall, made for the Roman military market, which has swirling enamel decoration in a Celtic style. In Britain, probably through preserved Celtic craft skills, enamel survived until the hanging bowls of early Anglo-Saxon art.
A problem that adds to the uncertainty over early enamel is artefacts (typically excavated) that appear to have been prepared for enamel, but have now lost whatever filled the cloisons or backing to a champlevé piece.This occurs in several different regions, from ancient Egypt to Anglo-Saxon England. Once enamel becomes more common, as in medieval Europe after about 1000, the assumption that enamel was originally used becomes safer.
In European art history, enamel was at its most important in the Middle Ages, beginning with the Late Romans and then the Byzantine, who began to use cloisonné enamel in imitation of cloisonné inlays of precious stones. The Byzantine enamel style was widely adopted by the "barbarian" peoples of Migration Period northern Europe. The Byzantines then began to use cloisonné more freely to create images; this was also copied in Western Europe.
Mosan metalwork often included enamel plaques of the highest quality in reliquaries and other large works of goldsmithing. Limoges enamel was made in Limoges, France, the most famous centre of vitreous enamel production in Western Europe, though Spain also made a good deal. Limoges became famous for champlevé enamels from the 12th century onwards, producing on a large scale, and then (after a period of reduced production) from the 15th century retained its lead by switching to painted enamel on flat metal plaques. The champlevé technique was considerably easier and very widely practiced in the Romanesque period. In Gothic art the finest work is in basse-taille and ronde-bosse techniques, but cheaper champlevé works continued to be produced in large numbers for a wider market.
Painted enamel remained in fashion for over a century, and in France developed into a sophisticated Renaissance and the Mannerist style, seen on objects such as large display dishes, ewers, inkwells and in small portraits. After it fell from fashion it continued as a medium for portrait miniatures, spreading to England and other countries. This continued until the early 19th century.
A Russian school developed, which used the technique on other objects, as in the Renaissance, and for relatively cheap religious pieces such as crosses and small icons.
From either Byzantium or the Islamic world, the cloisonné technique reached China in the 13–14th centuries. The first written reference to cloisonné is in a book from 1388, where it is called "Dashi ('Muslim') ware".No Chinese pieces that are clearly from the 14th century are known; the earliest datable pieces are from the reign of the Xuande Emperor (1425–35), which, since they show a full use of Chinese styles, suggest considerable experience in the technique.
Cloisonné remained very popular in China until the 19th century and is still produced today. The most elaborate and most highly valued Chinese pieces are from the early Ming Dynasty, especially the reigns of the Xuande Emperor and Jingtai Emperor (1450–57), although 19th century or modern pieces are far more common.
Japanese artists did not make three-dimensional enamelled objects until the 1830s but, once the technique took hold based on analysis of Chinese objects, it developed very rapidly, reaching a peak in the Meiji and Taishō eras (late 19th/ early 20th century).Enamel had been used as decoration for metalwork since about 1600, and Japanese cloisonné was already exported to Europe before the start of the Meiji era in 1868. Cloisonné is known in Japan as shippo, literally "seven treasures". This refers to richly coloured substances mentioned in Buddhist texts. The term was initially used for colourful objects imported from China. According to legend, in the 1830s Kaji Tsunekichi broke open a Chinese enamel object to examine it, then trained many artists, starting off Japan's own enamel industry.
Early Japanese enamels were cloudy and opaque, with relatively clumsy shapes. This changed rapidly from 1870 onwards.The Nagoya cloisonné company (Nagoya shippo kaisha existed from 1871 to 1884, to sell the output of many small workshops and help them improve their work. In 1874, the government created the Kiriu kosho kaisha company to sponsor the creation of a wide range of decorative arts at international exhibitions. This was part of a programme to promote Japan as a modern, industrial nation.
Gottfried Wagener was a German scientist brought in by the government to advise Japanese industry and improve production processes. Along with Namikawa Yasuyuki he developed a transparent black enamel which was used for backgrounds. Translucent enamels in various other colours followed during this period.Along with Tsukamoto Kaisuke, Wagener transformed the firing processes used by Japanese workshops, improving the quality of finishes and extending the variety of colours. Kawade Shibatarō introduced a variety of techniques, including nagare-gusuri (drip-glaze) which produces a rainbow-coloured glaze and uchidashi (repoussé) technique, in which the metal foundation is hammered outwards to create a relief effect. Together with Hattori Tadasaburō he developed the moriage ("piling up") technique which places layers of enamel upon each other to create a three-dimensional effect. Namikawa Sōsuke developed a pictorial style that imitated paintings. He is known for shosen (minimised wires) and musen (wireless cloisonné): techniques developed with Wagener in which the wire cloisons are minimised or burned away completely with acid. This contrasts with the Chinese style which used thick metal cloisons. Ando Jubei introduced the shōtai-jippō ( plique-à-jour ) technique which burns away the metal substrate to leave translucent enamel, producing an effect resembling stained glass. The Ando Cloisonné Company which he co-founded is one of the few makers from this era still active. Distinctively Japanese designs, in which flowers, birds and insects were used as themes, became popular. Designs also increasingly used areas of blank space. With the greater subtlety these techniques allowed, Japanese enamels were regarded as unequalled in the world and won many awards at national and international exhibitions.
Enamel was established in the Mughal Empire by around 1600 for decorating gold and silver objects, and became a distinctive feature of Mughal jewellery. The Mughal court was known to employ mīnākār (enamelers).These craftsmen reached a peak of during the reign of Shah Jahan in the mid-17th century. Transparent enamels were popular during this time. Both cloissoné and champlevé were produced in Mughal, with champlevé used for the finest pieces. Modern industrial production began in Calcutta in 1921, with the Bengal Enamel Works Limited.
Enamel was used in Iran for colouring and ornamenting the surface of metals by fusing over it brilliant colours that are decorated in an intricate design and called it Meenakari. The French traveller, Jean Chardin, who toured Iran during the Safavid period, made a reference to an enamel work of Isfahan, which comprised a pattern of birds and animals on a floral background in light blue, green, yellow and red. Gold has been used traditionally for Meenakari jewellery as it holds the enamel better, lasts longer and its lustre brings out the colours of the enamels. Silver, a later introduction, is used for artifacts like boxes, bowls, spoons, and art pieces while copper which is used for handicraft products was introduced only after the Gold Control Act, which compelled the Meenakars to look for a material other than gold, was enforced in India. Initially, the work of Meenakari often went unnoticed as this art was traditionally used as a backing for the famous kundan or stone-studded jewellery. This also allowed the wearer to reverse the jewellery as also promised a special joy in the secret of the hidden design.
More recently, the bright, jewel-like colours have made enamel a favoured choice for jewellery designers, including the Art Nouveau jewellers, for designers of bibelots such as the eggs of Peter Carl Fabergé and the enameled copper boxes of the Battersea enamellers,and for artists such as George Stubbs and other painters of portrait miniatures.
A resurgence in enamel-based art took place near the end of the 20th century in the Soviet Union, led by artists like Alexei Maximov and Leonid Efros. In Australia, abstract artist Bernard Hesling brought the style into prominence with his variously sized steel plates.
Enamel was first applied commercially to sheet iron and steel in Austria and Germany in about 1850. 5 Industrialization increased as the purity of raw materials increased and costs decreased. The wet application process started with the discovery of the use of clay to suspend frit in water. Developments that followed during the 20th century include enamelling-grade steel, cleaned-only surface preparation, automation, and ongoing improvements in efficiency, performance, and quality. :5:
Vitreous enamel can be applied to most metals. Most modern industrial enamel is applied to steel in which the carbon content is controlled to prevent unwanted reactions at the firing temperatures. Enamel can also be applied to gold, silver, copper, aluminium,stainless steel, and cast iron.
Vitreous enamel has many useful properties: it is smooth, hard, chemically resistant, durable, scratch resistant (5–6 on the Mohs scale), has long-lasting colour fastness, is easy to clean, and cannot burn. Enamel is glass, not paint, so it does not fade under ultraviolet light.A disadvantage of enamel is a tendency to crack or shatter when the substrate is stressed or bent, but modern enamels are relatively chip- and impact-resistant because of good thickness control and coefficients of thermal expansion well-matched to the metal.
The Buick automobile company was founded by David Dunbar Buick with wealth earned by his development of improved enamelling processes, c. 1887, for sheet steel and cast iron. Such enameled ferrous material had, and still has, many applications: early 20th century and some modern advertising signs, interior oven walls, cooking pots, housing and interior walls of major kitchen appliances, housing and drums of clothes washers and dryers, sinks and cast iron bathtubs, farm storage silos, and processing equipment such as chemical reactors and pharmaceutical process tanks. Structures such as filling stations, bus stations and Lustron Houses had walls, ceilings and structural elements made of enamelled steel.
One of the most widespread modern uses of enamel is in the production of quality chalk-boards and marker-boards (typically called 'blackboards' or 'whiteboards') where the resistance of enamel to wear and chemicals ensures that 'ghosting', or unerasable marks, do not occur, as happens with polymer boards. Since standard enamelling steel is magnetically attractive, it may also be used for magnet boards. Some new developments in the last ten years include enamel/non-stick hybrid coatings, sol-gel functional top-coats for enamels, enamels with a metallic appearance, and easy-to-clean enamels.
The key ingredient of vitreous enamel is finely ground glass called frit. Frit for enamelling steel is typically an alkali borosilicate glass with a thermal expansion and glass temperature suitable for coating steel. Raw materials are smelted together between 2,100 and 2,650 °F (1,150 and 1,450 °C) into a liquid glass that is directed out of the furnace and thermal shocked with either water or steel rollers into frit.
Colour in enamel is obtained by the addition of various minerals, often metal oxides cobalt, praseodymium, iron, or neodymium. The latter creates delicate shades ranging from pure violet through wine-red and warm grey. Enamel can be transparent, opaque or opalescent (translucent). Different enamel colours can be mixed to make a new colour, in the manner of paint.
There are various types of frit, which may be applied in sequence. A ground coat is applied first; it usually contains smelted-in transition metal oxides such as cobalt, nickel, copper, manganese, and iron that facilitate adhesion to the metal. Next, clear and semi-opaque frits that contain material for producing colours are applied.
Variants, and less common techniques are:
On sheet steel, a ground coat layer is applied to create adhesion. The only surface preparation required for modern ground coats is degreasing of the steel with a mildly alkaline solution. White and coloured second "cover" coats of enamel are applied over the fired ground coat. For electrostatic enamels, the coloured enamel powder can be applied directly over a thin unfired ground coat "base coat" layer that is co-fired with the cover coat in a very efficient two-coat/one-fire process.
The frit in the ground coat contains smelted-in cobalt and/or nickel oxide as well as other transition metal oxides to catalyse the enamel-steel bonding reactions. During firing of the enamel at between 760 to 895 °C (1,400 to 1,643 °F), iron oxide scale first forms on the steel. The molten enamel dissolves the iron oxide and precipitates cobalt and nickel. The iron acts as the anode in an electrogalvanic reaction in which the iron is again oxidised, dissolved by the glass, and oxidised again with the available cobalt and nickel limiting the reaction. Finally, the surface becomes roughened with the glass anchored into the holes.
Enamel coatings applied to steel panels offer protection to the core material whether cladding road tunnels, underground stations, building superstructures or other applications. It can also be specified as a curtain walling. Qualities of this structural material include:
We doubt if any form of the enameller's art can equal the work executed in Japan, which is distinguished by great freedom of design, and the most exquisite gradations of color.
A vase is an open container. It can be made from a number of materials, such as ceramics, glass, non-rusting metals, such as aluminium, brass, bronze, or stainless steel. Even wood has been used to make vases, either by using tree species that naturally resist rot, such as teak, or by applying a protective coating to conventional wood or plastic. Vases are often decorated, and they are often used to hold cut flowers. Vases come in different sizes to support whatever flower it is holding or keeping in place.
Cloisonné is an ancient technique for decorating metalwork objects with colored material held in place or separated by metal strips or wire, normally of gold. In recent centuries, vitreous enamel has been used, but inlays of cut gemstones, glass and other materials were also used during older periods; indeed cloisonné enamel very probably began as an easier imitation of cloisonné work using gems. The resulting objects can also be called cloisonné. The decoration is formed by first adding compartments to the metal object by soldering or affixing silver or gold as wires or thin strips placed on their edges. These remain visible in the finished piece, separating the different compartments of the enamel or inlays, which are often of several colors. Cloisonné enamel objects are worked on with enamel powder made into a paste, which then needs to be fired in a kiln. If gemstones or colored glass is used, the pieces need to be cut or ground into the shape of each cloison.
A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. The coating itself may be an all-over coating, completely covering the substrate, or it may only cover parts of the substrate. An example of all of these types of coating is a product label on many drinks bottles — one side has an all-over functional coating and the other side has one or more decorative coatings in an appropriate pattern to form the words and images.
Champlevé is an enamelling technique in the decorative arts, or an object made by that process, in which troughs or cells are carved, etched, die struck, or cast into the surface of a metal object, and filled with vitreous enamel. The piece is then fired until the enamel fuses, and when cooled the surface of the object is polished. The uncarved portions of the original surface remain visible as a frame for the enamel designs; typically they are gilded in medieval work. The name comes from the French for "raised field", "field" meaning background, though the technique in practice lowers the area to be enamelled rather than raising the rest of the surface.
Basse-taille (bahss-tah-ee) is an enamelling technique in which the artist creates a low-relief pattern in metal, usually silver or gold, by engraving or chasing. The entire pattern is created in such a way that its highest point is lower than the surrounding metal. A translucent enamel is then applied to the metal, allowing light to reflect from the relief and creating an artistic effect. It was used in the late Middle Ages, and then again in the 17th century.
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.
Overglaze decoration, overglaze enamelling or on-glaze decoration is a method of decorating pottery, most often porcelain, where the coloured decoration is applied on top of the already fired and glazed surface, and then fixed in a second firing at a relatively low temperature, often in a muffle kiln. It is often described as producing "enamelled" decoration. The colours fuse on to the glaze, so the decoration becomes durable. This decorative firing is usually done at a lower temperature which allows for a more varied and vidid palette of colours, using pigments which will not colour correctly at the high temperature necessary to fire the porcelain body. Historically, a relatively narrow range of colours could be achieved with underglaze decoration, where the coloured pattern is applied before glazing, notably the cobalt blue of blue and white porcelain.
This is a list of pottery and ceramic terms.
Substrate is a term used in materials science to describe the base material on which processing is conducted to produce new film or layers of material such as deposited coatings.
Glass casting is the process in which glass objects are cast by directing molten glass into a mould where it solidifies. The technique has been used since the Egyptian period. Modern cast glass is formed by a variety of processes such as kiln casting, or casting into sand, graphite or metal moulds.
Limoges enamel has been produced at Limoges, in south-western France, over several centuries up to the present. There are two periods when it was of European importance. From the 12th century to 1370 there was a large industry producing metal objects decorated in enamel using the champlevé technique, of which most of the survivals, and probably most of the original production, are religious objects such as reliquaries.
A chasse, châsse or box reliquary is a shape commonly used in medieval metalwork for reliquaries and other containers. To the modern eye the form resembles a house, though a tomb or church was more the intention, with an oblong base, straight sides and two sloping top faces meeting at a central ridge, often marked by a raised strip and decoration. From the sides there are therefore triangular "gable" areas.
Plique-à-jour is a vitreous enamelling technique where the enamel is applied in cells, similar to cloisonné, but with no backing in the final product, so light can shine through the transparent or translucent enamel. It is in effect a miniature version of stained-glass and is considered very challenging technically: high time consumption, with a high failure rate. The technique is similar to that of cloisonné, but using a temporary backing that after firing is dissolved by acid or rubbed away. A different technique relies solely on surface tension, for smaller areas. In Japan the technique is known as shotai-jippo, and is found from the 19th century on.
Ando Cloisonné Company is a Japanese cloisonné making company located in Sakae, Nagoya, central Japan.
Industrial porcelain enamel is the use of porcelain enamel for industrial, rather than artistic, applications. Porcelain enamel, a thin layer of ceramic or glass applied to a substrate of metal, is used to protect surfaces from chemical attack and physical damage, modify the structural characteristics of the substrate, and improve the appearance of the product.
China painting, or porcelain painting, is the decoration of glazed porcelain objects such as plates, bowls, vases or statues. The body of the object may be hard-paste porcelain, developed in China in the 7th or 8th century, or soft-paste porcelain, developed in 18th-century Europe. The broader term ceramic painting includes painted decoration on lead-glazed earthenware such as creamware or tin-glazed pottery such as maiolica or faience.
The craft of cloisonné enameling is a metal and glass-working tradition practiced in the Byzantine Empire from the 6th to the 12th century AD. The Byzantines perfected an intricate form of vitreous enameling, allowing the illustration of small, detailed, iconographic portraits.
Enamelled glass or painted glass is glass which has been decorated with vitreous enamel and then fired to fuse the glasses. It can produce brilliant and long-lasting colours, and be translucent or opaque. Unlike most methods of decorating glass, it allows painting using several colours, and along with engraving, has historically been the main technique used to create the full range of image types on glass.
The Khalili Collection of Japanese Art is a private collection of decorative art from Meiji-era (1868–1912) Japan, assembled by the British-Iranian scholar, collector and philanthropist Nasser D. Khalili. Its 1,400 art works include metalwork, enamels, ceramics, lacquered objects, and textile art, making it comparable only to the collection of the Japanese imperial family in terms of size and quality. The Meiji era was a time when Japan absorbed some Western cultural influences and used international events to promote its art, which became very influential in Europe. Rather than covering the whole range of Meiji-era decorative art, Khalili has focused on objects of the highest technical and artistic quality. Some of the works were made by artists of the imperial court for the Great Exhibitions of the late 19th century. The collection is one of eight assembled, published, and exhibited by Khalili.
The Khalili Collection of Enamels of the World is a private collection of enamel artworks from the period 1700 to 2000, assembled by the British-Iranian scholar, collector and philanthropist Nasser D. Khalili. It is one of the eight Khalili Collections, each of which is considered among the most important in its field.
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