Benvenuto Cellini recommends a little paper sponge to be used in smoothing the face of enamels. "Take a clean nice piece of paper," he writes, "and chew it well between your teeth,—that is, if you have got any—I could not do it, because I've none left!"
A celebrated piece of goldsmith's work of the tenth century is the Pala d'Oro at St. Mark's in Venice. This is a gold altar piece or reredos, about eleven feet long and seven feet high, richly wrought in the Byzantine style, and set with enamels and precious stones. The peculiar quality of the surface of the gold still lingers in the memory; it looks almost liquid, and suggests the appearance of metal in a fluid state. On its wonderful divisions and arched compartments are no less than twelve hundred pearls, and twelve hundred other precious gems. These stones surround the openings in which are placed the very beautiful enamel figures of saints and sacred personages. St. Michael occupies a prominent position; the figure is partly in relief. The largest medallion contains the figure of Christ in glory, and in other compartments may be seen even such secular personages as the Empress Irene, and the Doge who was ruling Venice at the time this altar piece was put in place—the year 1106. The Pala d'Oro is worked in the champlevé process, the ground having been cut away to receive the melted enamel. It is undoubtedly a Byzantine work; the Doge Orseolo, in 976, ordered it to be made by the enamellers of Constantinople. It was not finished for nearly two centuries, arriving in Venice in 1102, when the portrait of the Doge then reigning was added to it. The Byzantine range of colours was copious; they had white, two reds, bright and dark, dark and light blue, green, violet, yellow, flesh tint, and black. These tints were always fused separately, one in each cloison: the Greeks in this period never tried to blend colours, and more than one tint never appears in a compartment. The enlarging and improving of the Pam d'Oro was carried on by Greek artists in Venice in 1105. It was twice altered after that, once in the fourteenth century for Dandolo, and thus the pure Byzantine type is somewhat invaded by the Gothic spirit. The restorations in 1345 were presided over by Gianmaria Boninsegna.
One of the most noted specimens of enamel work is on the Crown of Charlemagne,[1] which is a magnificent structure of eight plaques of gold, joined by hinges, and surmounted by a cross in the front, and an arch crossing the whole like a rib from back to front. The other cross rib has been lost, but originally the crown was arched by two ribs at the top. The plates of gold are ornamented, one with jewels, and filigree, and the next with a large figure in enamel. These figures are similar to those occurring on the Pala d'Oro.
[Footnote 1: See Fig. 1.]
| DETAIL; SHRINE OF THE THREE KINGS, COLOGNE |
The Shrine of the Three Kings in Cologne is decorated both with cloisonné and champlevé enamels,—an unusual circumstance. In Aix la Chapelle the shrine of Charlemagne is extremely like it in some respects, but the only enamels are in champlevé. Good examples of translucent enamels in relief may be seen on several of the reliquaries at Aix la Chapelle.
Theophilus gives us directions for making a very ornate chalice with handles, richly embossed and ornamented with mello. Another paragraph instructs us how to make a golden chalice decorated with precious stones and pearls. It would be interesting as a modern problem, to follow minutely his directions, and to build the actual chalice described in the eleventh century. To apply the gems and pearls Theophilus directs us to "cut pieces like straps," which you "bend together to make small settings of them, by which the stones may be enclosed." These little settings, with their stones, are to be fixed with flour paste in their places and then warmed over the coals until they adhere. This sounds a little risky, but we fancy he must have succeeded, and, indeed, it seems to have been the usual way of setting stones in the early centuries. Filigree flowers are then to be added, and the whole soldered into place in a most primitive manner, banking the coals in the shape of a small furnace, so that the coals may lie thickly around the circumference, and when the solder "flows about as if undulating," the artist is to sprinkle it quickly with water, and take it out of the fire.
Niello, with which the chalice of Theophilus is also to be enriched, stands in relation to the more beautiful art of enamel, as drawing does to painting, and it is well to consider it here. Both the Romans and the Anglo-Saxons understood its use. It has been employed as an art ever since the sixth and seventh centuries. The term "niello" probably is an abbreviation of the Italian word "nigellus" (black); the art is that of inlaying an engraved surface with a black paste, which is thoroughly durable and hard as the metal itself in most cases, the only difference being in flexibility; if the metal plate is bent, the niello will crack and flake off.
| FINIGUERRA'S PAX, FLORENCE |
Niello is more than simply a drawing on metal. That would come under the head of engraving. A graver is used to cut out the design on the surface of the silver, which is simply a polished plane. When the drawing has been thus incised, a black enamel, made of lead, lamp black, and other substances, is filled into the interstices, and rubbed in; when quite dry and hard, this is polished. The result is a black enamel which is then fused into the silver, so that the whole is one surface, and the decoration becomes part of the original plate. The process as described by Theophilus is as follows: "Compose the niello in this manner; take pure silver and divide it into equal parts, adding to it a third part of pure copper, and taking yellow sulphur, break it very small... and when you have liquefied the silver with the copper, stir it evenly with charcoal, and instantly pour into it lead and sulphur." This niello paste is then made into a stick, and heated until "it glows: then with another forceps, long and thin, hold the niello and rub it all over the places which you wish to make black, until the drawing be full, and carrying it away from the fire, make it smooth with a flat file, until the silver appear." When Theophilus has finished his directions, he adds: "And take great care that no further work is required." To polish the niello, he directs us to "pumice it with a damp stone, until it is made everywhere bright."