FORMING After purifying the materials, the makers had to combine them. They stepped on the materials with their feet in large wooden recipients made specifically for this until they had formed a homogeneous paste, hard and compact. After this, they would manually knead it piece by piece over slates. At this point, they had to be careful to eliminate any saline trace, because the tiniest impurity could ruin the whole paste.Â
Porcelain vases were made either with lathes or cast molds. Vases were usually made in molds, while small pieces like plates, cups, bowls, were made with a lathe. The relief works were molded and then finished with a chisel. Each section of the piece had its own mold, which were eventually combined into a full figure. The dough had to be kneaded until it softened, and then forcefully and manually made to fit the mold. In SĂ¨vres, an apparatus helped force the dough into the mold with compressed air.Â
Every piece formed on molds was finished by hand with the aid of instruments that helped the maker unite, polish, cut and add different parts such as flowers and fruits, besides evening out any possible flaws. Therefore, the worker who finished the pieces had to be skilled in sculpture.
1st FIRING Porcelain is fired so that the body can retain its shape and become non-porous. Porcelain kilns were build with a special geometry made for the most effective firing of the pieces. When the porcelain pieces were in the kiln, they were put inside large clay vases which protected them from direct contact with flames. Meissen hard-paste porcelain was only fired once, at higher temperatures, to seal everything together.
Soft-paste porcelain, however, was fired twice at lower temperatures and this 1st firing was known as Biscuit. Cooked before the addition of glaze, at this point the porcelain had a matte look.
The trick to know if the porcelains were ready for glazing was to, once in a while, take little pieces out of the oven, let them cool and them put them on the tongue: if they were sticky, it meant the biscuit was well cooked and ready for glazing.
The differences in temperature between hard and soft-paste porcelain allowed different ranges of decoration colors.
2nd FIRING The final firing of the porcelain was the most delicate step of the whole operation. Pieces had to be properly arranged inside the kiln. They were put inside large clay vases filled with sand, to prevent the porcelain and the clay from mixing at the high firing temperature. The vases were then piled up to the kilnâ€™s roof. The pieces were also arranged so they would all be evenly exposed to the kilnâ€™s heat. It was important to label both the pieces and the clay boxes so that if something went wrong during this step, the maker could know exactly what needed to be remade.
Sometimes the kiln heat vitrified the sand around the porcelain and stuck to its surface, so workers were especially hired to cut and polish off this excess material.
DECORATING To make the colors liquid and paintable, gums, oils and sugar were used. Each option had its problems: sugar attracted flies which ate colors and destroyed drawings before they were dry; dried gums sometimes peeled off because they were not very adherent; and the solubility of essential oil could blur drawing outlines.
Nicolas-Christiern de Thy, comte de Milly. L’art de la porcelaine, Plate VIII, 1772.
Friedrich Reinhold. Sketch in oil showing the painters' workshop at the Imperial Porcelain Manufactory in Vienna, c. 1830.
Because soft paste was fired at a lower temperature, its range of color possibilities was wider than hard paste’s. Even though it produced soft-paste “fake” porcelain, the Sèvres manufacture conquered the European market from Meissen with its bright and lavish colors by the end of the 18th century.