Enamel painting is usually done on a background of opaque white enamel, although other opaque colors are sometimes used. The metal must be prepared in the regular manner, and one or two coats of enamel charged and fired, the last coat being fired to as perfect smoothness as possible. Instead of flushing the enamel smooth it is often advisable to stone and fire it, by which processes a smoother surface is obtained.

After this last firing, the black flakes of metallic oxide which will be found on the metal should be brushed away, leaving the piece clean and ready to be painted. It is desirable not to have too thick a layer of enamel, as in that case it is apt to chip off in some of the later firings. If, on the other hand, the enamel layer is thin, it is quite difficult to get it smooth.

Any picture desired may now be painted on the enamel surface, either with ordinary china paints or finely ground enamel “slimes” mixed with oil of cloves or oil of lavender. This painting may be done with a small camel’s-hair brush and when finished should be fired until the enamel fuses. The piece should be allowed to cool slowly and when cool should be charged with a coat or two of clear fondant which, after being fired, may or may not be stoned and polished, as the artist sees fit. If the painting requires it, it may be touched up and fired several times before being charged with the fondant, but the fewer times a piece is fired the less chance there is for accidents which may prove fatal to the work of art.

If the metal used is very thin, it will be necessary to enamel it on the back as well as on the front, for a thin piece of metal which is enameled on one side only will warp out of shape, but if enameled on both sides will keep its shape perfectly. Of course the enamel on the back may be of any color and need not be finished carefully, as it is there for use not ornament.

An enamel painting must be fired with great care. First it must be warmed by degrees before put into the muffle, so that the oil may have a chance to evaporate. It should then be placed partly in the muffle and not put way in and should not be heated to a red heat until the residues of the oils shall have burnt away. If too hot a muffle is used, or if the piece is fired too long, the painting will appear blurred and faint. If the painting appears blistered after firing, it is due to the fact that the oils used contained too much carbonaceous residue.

The fondant used on an enamel painting should be very finely ground, much more so than for ordinary work, and the first layer of fondant should not be fired to smoothness but only until it just begins to flow, as was the case with the painting itself. The last layer of fondant should of course be fired as smooth as possible.

If a large number of pieces are to be painted with the same design, there are a number of mechanical means that can be used to take the place of free-hand painting. We will outline one of these processes, which is as follows.

Etch a copper plate with the outline of the design that is to be painted on the enamel. The etching on the copper plate must be a positive, not a negative; that is, the design must appear on the plate as it is to appear on the enamel and not reversed as in ordinary etching. The design must also be exactly the same size as the one to appear on the enamel.

The lines in the etching should now be filled with finely ground enamel paints mixed with oil of cloves or some such medium. It is best to use paint of the color that is to predominate in the picture, although in some cases it will be found that black will give the best working outline.

When the lines of the etching are filled with the paint, the plate should be scraped smooth so that no paint remains on it except in the etched lines. The plate should now be pressed against a piece of thin, smooth, sheet rubber, to which the paint will stick in preference to the copper plate, thus transferring the design to the sheet of rubber, where it appears reversed.

The rubber with the design side down is now pressed upon the smooth surface of the white enamel, which should be prepared in the same way as it would be prepared for regular painting. The design is thus transferred from the rubber to the enamel surface, where it appears again positive.

The enamel surface now has on it the outline of the design either in black or in color as the case may be. From this point on, the process is the same as in regular hand painting on enamel, but as the outline has been blocked in, the work is considerably easier. A speed and uniformity are obtained by this process which it is difficult to equal with free-hand work.

Another process whereby a number of similar designs can be easily executed is by decalcomania. Decalcomania pictures are made in Germany and can be obtained through any artists’ supply house. In this case the white enamel background is obtained in the usual manner, after which a decalcomania picture is transferred to the enamel surface. The enamel is first covered with a very thin layer of size or gum as in the case of foils. When the size becomes sticky, the decalcomania picture should be placed face downwards on the enamel. The paper on the back of the picture should now be wet with a sponge until it becomes loose, when it should be removed and the remaining scum washed off with plenty of clean water. The piece after being dried thoroughly is ready to be fired. The rest of the process is the same as in regular painted enamel work. Great care must be taken in firing the decalcomania work.