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.
CHAPTER IX
PHOTOGRAPHS ON ENAMEL
There are several methods by which photographs may be reproduced upon enamel. However, since they are rather difficult, we will explain only one method, and for the other processes will refer the student to Dr. Paul Liesegang’s treatise on photographing on enamel, porcelain, and glass, which is printed in German.
In the first place only the best quality of mirror glass should be used for the plates, as it is essential that they should be perfectly smooth and without blemishes. The glass should then be cut the same size as the negative plate which is to be used later. The glass plate must be made perfectly clean, which is best done by placing it in a mild sulphuric acid bath for about ten minutes and then washing it well with clean water. It should be dried with a clean cloth or tissue paper, after which it may be wrapped in clean dry tissue paper and kept in a dry place until needed.
Fig. 10. Polishing.
Out of the many receipts for preparing the sensitive solution, we will give only the two most generally found satisfactory. These are as follows: