ENAMEL (Fr. email, originally email, from the same root as smelt), the name given to vitrified substances of various composition applied to the surface of metals. Enam eling is practiced (1) for purposes of utility, as in making the dial-plates of watches and clocks, coating the insides of culinary vessels, etc., when it may be considered as belong ing to the useful arts; and also (2) for producing objects of ornament and beauty—artistic designs, figures, portraits, etc., when it belongs to the fine arts. Both the composition of enamels and the processes of applying them are intricate subjects, besides being in many cases kept secret by the inventors: and we can only afford space for the most general indications of their nature. The basis of all enamels is an easily fusible color less silicate or glass,•to which the desired color and the desired degree of opaqueness are imparted by mixtures of metallic oxides. The molten mass, after cooling, is reduced to a fine powder, and washed, and the moist paste is then usually spread with a spatula upon the surface of the metal; the whole is then exposed in a surface (fired, as it is called) till the E. is melted, when it adheres firmly to the metal. The metal most commonly used as a ground for E. is copper; but for the finest kinds of enamel-work gold and silver are also used.
Artistic or Ornamental Enameling.—This art is of great antiquity: it is proved by the remains found in Egypt to have been practiced there; from the Egyptians it passed to the Greeks, and it was extensively employed in decoration by the Romans; in the reign of Augustus, the Roman architects began to make use of colored glass in their mosaic deco rations; various Roman antiquities, ornamented with E., have been dug up in Britain, and it was adopted there by the Saxons and Normans. A jewel found at Atheiney, in Somersetshirc, and now preserved in the Ashmolean museum at Oxford, is proved by the inscription on it to have been made by order of Alfred; and there are various figures with draperies partly composed of colored E. on the sides of the gold cup given by king John to the corporation of Lynn, in Norfolk.
Enameling has been practiced from a remote period in the east, Persia, India, and China, under a separate and distinct development; but there is nothing from which it can be inferred that the various methods were in use earlier than in Europe. As a deco ration, enameling was more popular, and attained to greater perfection in the middle ages than in classic times. It was extensively practiced at Byzantium from the 4th until the 11th c., and afterwards in Italy in the Rhenish provinces, and at Limoges in the s. of France, where it was successfully followed out till a comparatively late period, in several different styles. The Byzantine and other early styles of enamel-work down to the 17th c. were generally employed in ornamenting objects connected with the service of the church, such as reliquaries, pyxcs, church-candlesticks, crosiers, portable altars, the frontals of altars, etc:; the art was also greatly used in ornamenting jewelry, and vessels made for use or display in the mansions of the rich, such as salt-cellars, coffers, ewers, plateaux, candlesticks, etc. After this period the art declined, until a new phase of it was invented in France, in which E. is used as a ground, and the figures are painted with vitrified colors on the surface of it. This is enamel-painting properly so-called, the earlier styles being more of the nature of mosaics.
Distinguished with reference to the manner of execution, enamel-work may be divided into four kinds: 1. Cloisonee, or inclosed, the method of the Byzantine school, in which the design is formed in a kind of metal case, generally gold or copper, and.the several colors are separated by very delicate filagree gold bands, to prevent them running into each other. 2, Champ Eng, practiced by the early Limoges school. In this process the ornamental design, or the figures that were to be tilled in with color, were cut in the metal (generally copper) to some depth ; and wherever two colors met, a thin partition of the metal was left, to prevent the colors running into each other by fusion when fired. 3. Translucent E., which had its origin, and was brought to great perfection in Italy, was composed of transparent E. of every variety of color, laid in thin coatings over the design, which was incised on the metal, generally silver, the figure or figures being slightly raised in low relief, and marked with the graver, so as to allow the drawing of the contours to be seen through the ground, instead of being formed by the coarse lines of the copper, as in the early Limoges enamels. 4. Surface-painted enamels, which may be divided into two stages. The first stage, which is known as the late Limoge style, sprang up under Francis I. of France (1515-47). In this the practice was to cover the metal plate with a coating of dark E. for shadows, and to paint on this with white, sometimes set off with gold hatchings, sometimes having the hands and other parts of the figures completely colored. The designs were generally taken from well-known paintings or engravings of the period; and the style of the designs was strongly influenced by that of the Italian artists employed by Francis I. This style soon degenerated, and gave place to the latest or miniature style, which was invented before the middle of the 16th c. by Jean Toutle, a goldsmith at Chateaudun, and carried to the highest perfection by Jean Petitot, a miuiature-painaer, who was born at Geneva, 1607, and afterwards resided long in England, and then in Paris. In this the plate is covered with a white opaque E., and the colors are laid on this with a hair-pencil, and fixed by firing. The paints are prepared by grinding up colored enamels with some kind of liquid, and when fused by the heat, they become incorporated with the E. of the ground. The earlier enamelers of this school occupied themselves with miniatures, snuff-boxes, and other trinkets, till the period of the French revolution, when the art fell into disuse. It was, however, revived in England early in this century; and copies of portraits and pictures on a much larger scale than the French miniatures were executed with much success by the late H. Bone, WA , and the late Charles Muss. Works of this description possess the obvious advantage of durability; but those various qualities of texture, and the delicacy of color for which good works in oil or water-color are prized, cannot be attained in E. copies; and it is to be regretted that greater efforts are not made to turn enameling to account in the way of ornamentation, for which it is so admirably fitted, rather than in attempts at imitating works classed strictly as within the bounds of fine art, and to put in practice the older styles of enameling, particularly those denominated champ leve and transparent enameling.