Summary :
For a long time, "cloisonne" was only made under the supervision of the court. In the 19th century the technique passed into the hands of the people and became one of the 8 greatest works of Yanjing. It developed and spread as a cottage industry in the surrounding area for some time. But the tedious cost of such craftsmanship caused the loss of cloisonné in these regions.
Cloisonne can be classified as metal, but because of its enamelling it is often incorrectly classified as porcelain.
A fine cloisonné production should have a lustrous color, heavy and solid bone, neat and even aisles and brilliant gilding. There are many different cloisonné glazes, but the most common colors are sky blue (pale blue), sapphire blue (lapis lazuli), red (chicken's blood), light green (grass green), green dark (vegetable jade, translucent), white (checkerboard), grape purple (vitreous amethyst), purple red (pink) and emerald blue (between sky blue and sapphire blue, with a bright color)
The principle of cloisonné is to imprison the enamel in circuits formed by the thin partitions made of flat copper wire welded to the body of the object, the result being the colored patterns. This technique has very ancient origins in the Near East. It was used by the Egyptian Pharaohs in the 19th century BC.
Enamels on metal must have been introduced in China during the Yuan dynasty. Surviving pieces from this era are rare and are found in imperial palaces on both sides of the Taiwan Strait. Most of the pieces are decorated with an established lotus pattern: The flowers are blooming and full, spreading, accompanied by small buds. The branches and leaves are fleshy and spread freely, adapting to the space given to them. Although the craft with its concepts of intertwined lotuses originated in Western Asia, the Chinese style has internalized it as a whole without changing anything. Grape patterns are also sometimes found in symmetrical compositions.
The cloisonné process is complex.
- Manufacture of the tire, or shaping of the shape.
- Filigree or adhesion of fine flattened, pinched, broken threads in order to form varied and fine patterns.
- Welding at high temperature (900°) the brass wire patterns on the brass tire.
- Pointing (pointing blue): Enamel is a lustrous, opaque or translucent substance, obtained by the fusion of raw materials such as lead, borate and glass powder, which, together with different oxidized metals, become enamels of different colors, also called enamels. When the enamel is cooled it becomes solid and is then ground into a fine powder and mixed with water before being filled. The glazes are then added to the solvent to create glazes of different colors, and the different glazes are filled in using metal spatulas according to the contours of the watermark.
- Firing blue: Glazes (called blue, because early glazes were mostly blue) are fired in the oven at a temperature of 800-1000°C to melt the glaze into a powder. The size of the enamel is then reduced by about 1/3, and in order for the surface not to be uneven, it is necessary to fill it several times with enamel of the same color. Glazing was repeated two to three or four times to ensure that the surface of the glaze was flattened against the wire without pitting.
- Polishing: The piece is placed in water and polished with coarse gravel, yellow stones and charcoal to smooth out any unevenness in the blue enamel, then with charcoal and a scraper to smooth out the scratch lines. copper, base lines and mouth lines that are not covered with blue enamel.
- Gilding: A flattened and polished cloisonne is acid washed, decontaminated and sanded, then placed in a gilding bath and ionized to allow the gold to adhere to the unglazed metal body. The purpose of gilding is to prevent corrosion and rusting of the metal body and to make the object look shiny, new and glorious. After washing and drying, the piece is then finished with a beautiful cloisonné.
The Chinese already possessing metallurgical skills for casting copper and for making glass and glaze, not to mention their knowledge of forging, quickly seized on cloisonné with success. Plus it fit in with what they had already developed: jade, jewelry, and fine china.