Berlin European Porcelain
Berlin, the fourth Royal factory, was first established in 1750 by a merchant named Wegeli. In 1761 it belonged to the banker Gottskowski, who, in 1763, sold it to Frederick the Great for the then enormous sum of eight hundred and forty thousand francs (about the value of six hundred thousand dollars today). This royal factory has produced only true porcelain. Frederick took great interest in his purchase, and among other decrees issued by him for its advantage was the following, repealed in 1787: "That in place of other special levies upon the Jews, each Jew should upon his marriage purchase from five to twelve thousand thalers of porcelain according to his estate." This resulted in great injury to this beautiful porcelain, and drew upon it the name of the porcelain of the Jews. Berlin had the honor in 1791 of having as one of its "Commissioners on Colors," the great Alexander von Humboldt. At Berlin were produced many fine works and of great varieties. The decorations have been fully equal to any factory outside of Sevres, whose fine pieces were sometimes reproduced, but always under the Berlin mark.
Lithophanie was here invented; it consists of making pictures in which the shades are produced by varying the thickness of the paste. Whilst at this factory Pott invented the method of transferring line engravings or colored prints to porcelain.
True porcelain, or, as it is often called, hard paste porcelain, is composed of petunse and kaolin with a kaolinic glaze. In baking it requires the highest temperature of a white heat to effect the proper junction between the particles of petunse, which never fuses, and the kaolin.
The only colors which will not burn out under this great heat are cobalt blue, and a dull red used by the Chinese. These two colors, therefore, are the only ones found applied under the glaze on true porcelain; all others have to be applied as an enamel upon the surface of the glaze, and fixed by a second baking at a lower temperature. The imitation of porcelain, known as "soft paste," was made in Europe before the discovery of kaolin, and therefore lacks the important element of true porcelain. Its paste consists of petunse and a composite substitute for kaolin formed of nitre, sea-salt, alum, soda, gypsum, white chalk and marl, which are varied in different factories.
This paste, like that of true porcelain, is translucid, it is soft to the touch, and bakes at a low temperature. In the oven great care has to be exercised, as the least excess of heat will reduce it to fragments. For this reason also hard kaolinic glaze, which requires great heat, cannot be used upon it. The glaze applied must be such as will fuse at a low temperature; alkaline or plumbeous compounds are therefore used, which, after firing, can easily be scratched with a steel. This quality we presume has led to the misnomer of soft paste porcelain.
( Originally Published Late 1800's )