Enamel is “charged,” or put on the metal, in the form of a watery mud, by means of a small spatula. The most convenient spatula is one made from a piece of steel wire about the size of a crochet needle and flattened at one end. In fact a crochet needle itself, flattened at one end, or even the small blade of a penknife, will be found quite serviceable. If this spatula is mounted in a wooden handle made from a penholder it will be found very easy to handle.

A small daub of very watery enamel should be taken on the end of the spatula and laid upon the metal where it is to be enameled. If the surface to be enameled is very large, a larger spatula can be used to advantage. If the enamel is too watery it will not stick to the spatula while being taken from the palette, and if it is too dry it cannot be readily transferred from the spatula to the metal.

When the piece has been entirely covered with enamel, it should be held in the hand and tapped gently with the spatula. If the enamel is wet enough this procedure will spread it evenly over the metal. The water should now be drawn off from the enamel by means of a clean piece of cloth or blotting paper. The remaining moisture will soon evaporate, leaving the enamel perfectly dry. Only when perfectly dry is it in a condition to be fired.

Care must be taken not to get the enamel on too thick, as in that case it will chip off when fired. On the other hand, enamel shrinks considerably on being fired, so if it is put on too thin it is apt to shrink, leaving bare spaces of metal. The proper thickness with which to charge a piece of work can only be learned by experiment, and in most cases it is desirable to charge a piece with several thin coats rather than with one thick one.

In cloisonnÉ and champlevÉ work it is generally necessary to use at least two coats in order to bring the enamel up to the level of the metal parts. Originally in these kinds of enameling the idea was to have each color or shade of enamel separated by a metal wall from every other shade, which made the charging comparatively simple. Now the vulgar modern taste permits several different shades side by side without partitions, or even blended. If the enamel is not too wet two distinct colors can be charged side by side without having them run into each other to any appreciable extent. They may then be fired, and they will be no more mixed in that process than they were before it.

A blend between two colors may be obtained by mixing two enamels together and then charging the piece with the mixture. Such a mixture when fired is often found to be speckled instead of a clear shade. If, after mixing, the enamel is ground finer, this speckled effect can sometimes be eliminated. This process is by no means always satisfactory.

Another way that two colors can be blended is as follows: Divide a piece to be enameled into three parts by two imaginary lines and call the parts A, B, and C. Now charge A and B with a thin coat of, for instance, blue, and C with a thin coat of red, and fire the piece. Then on the second charging charge A with blue and B and C with red. When fired, part B will be found intermediate between A and C, in this case a sort of purple. This purple may be made bluish or reddish, as desired, by using a preponderance of blue or of red enamel. This preponderance can be largely regulated by the thickness of the layers or coats of each color, although the last coat, other things being equal, will, on account of its position, exert by far the stronger influence.

With most transparent colors it is desirable, though not necessary except in the case of so-called “opals,” to use an under layer of fondant, that is, on the first charging, to cover the entire surface with a thin layer of transparent white or colorless enamel, commonly called flux or fondant. This under layer of fondant is used more on gold than on silver or copper, but in any case it will greatly enhance the brilliancy of the enamels. It is of great assistance in bringing out delicate colors and especially “opals,” for if opals are charged directly upon the stock they have a strong tendency to become opaque when fired. Some delicate roses and pinks if put directly upon the metal will “fire” black, while over a layer of fondant they became beautiful and delicate shades.

Where several colors are used on the same piece it is generally advantageous to use fondant for the last layer. The advantage of this is that the harmony and qualities of the different colors are then not affected by the stoning and polishing, which no matter how carefully done are bound to cut down the enamel, and in the case of transparent colors the thinner a layer becomes the lighter it becomes.

Any transparent color can be made lighter either by being stoned down or by being put on over a layer of fondant. Transparent white can easily be obtained on silver by the use of bluish and white fondants, but it is impossible to obtain transparent white on gold or copper unless these metals are first plated with silver.

Most enamels appear to best advantage on silver over fondant, and when the same enamel is put on another metal it changes its hue. This change of hue varies with each individual enamel and can only be learned by experiment. In general, white (fondant) on silver becomes pink on gold or copper, orange becomes red, yellow becomes orange or brown, blue has a tendency to green and green to yellow. Opaque colors of course do not actually change color, but owing to the different color of their setting they often give different effects.

Some shades that cannot be obtained by mechanically mixing opaque colors or by layers of different transparent colors, can be obtained by putting a layer of transparent enamel over a layer of opaque. Opaque white as an under layer will often give a desirable shade to a transparent enamel which is not just the color required.