Vitreous enamel

In a discussion of art or technology, enamel (or vitreous enamel, or porcelain enamel in American English) is the colorful result of fusion of powdered glass to a substrate through the process of firing, usually between 750 and 850 degrees Celsius. The powder melts and flows to harden as a smooth, durable vitreous coating on metal, glass or ceramic. It is often applied in a paste form and may be transparent or opaque when fired. Vitreous enamel can be applied to most metals.

Also, an "enamel" is a decorative object, usually very small, having an enamel coating, such as a piece of champlevé or cloisonné.

Vitreous enamel has many excellent properties: it is smooth, hard, chemically resistant, durable, can take on long-lasting, brilliant colors, and cannot burn. Disadvantages are its tendency to crack or shatter when the substrate is stressed or bent.

The durability of enamel has given it many functional applications, including: early 20th century advertising signs, interior walls of ovens, speckleware cooking pots, exterior walls of high quality kitchen appliances, cast iron bathtubs, storage silos on farms and process equipment such as chemical reactors and tanks for the chemical and pharmaceutical process industries.

Enamelling is an old and widely-adopted technology. The ancient Egyptians applied enamels to pottery and stone objects. Other practitioners include the ancient Greeks, Celts, Russians, and the Chinese.

The bright, jewel-like colors have also made enamel a favored choice for designers of jewelry and bibelots, such as ancient beads, the fantastic eggs of Peter Carl Fabergé , enameled copper boxes of Battersea enamellers, and artists such as George Stubbs and other painters of portrait miniatures. Enameling was a favorite technique of the Art Nouveau jewellers.

According to some sources, the word enamel comes from the High German word smelzan (to smelt) via the Old French esmail.

Some techniques of enameling:

• Basse-taille, from the French word meaning "low-cut." The surface of the metal is decorated with a low relief design which can be seen through translucent and transparent enamels.
• Champlevé, French for "raised field" where enamel is fired around raised fields of metal, leaving the metal exposed.
• Cloisonné, French for "cell", where thin copper or gold wires form walls which separate differently colored areas.
• Counter enameling, where a thin layer of enamel is aplied to the back of a piece as well - sandwiching the metal - to create less tension on the glass so it doesn't crack.
• Grisaille, French term meaning "greying," where dark blue or black background is applied, then a special white colour is aplied on top, building up designs.
• Limoges, named after the town in France where the technique was invented, is the technique of "painting" with enamel to form a detailed picture.
• Plique-à-jour, French for "braid letting in daylight" where the enamel has no backing so light can shine through the thin layer.
• Ronde bosse, French for "round bump." A 3D type of enameling where a sculptural form is completely enameled.
• Stenciling, where a stencil is placed over the work and the powdered enamel is sprinkled over the top. The stencil is removed before firing, the enamel staying in a pattern, slightly raised.

Color in enamel is obtained by the addition of various minerals, often based on the elements cobalt, praseodymium, iron, or neodymium. The last creates delicate shades ranging from pure violet through wine-red and warm gray. Enamel can be either transparent or opaque. You cannot mix different enamel colours to make a new colour as you can with paint. You will end up with tiny specs of both colours.

See also:

• Cloisonné
• Nineveh
• Rostov the Great
• Silicon

External links

Mechanical and Physical Properties of Vitreous Enamel (http://www.porcelainenamel.com/pei502.htm)

Institute of Vitreous Enamellers (UK) (http://www.ive.org.uk/index.htm)

Deutscher Emailverband (German Enamel Association (DE)) (http://www.emailverband.de)

"Enamel" paint

Some paints are called "enamel paints". This is a commonly used, yet fanciful term, implying that an ordinary latex or oil-based paint has the same properties as true, fired enamel.de:Email eo:Emajlo nl:Email