景泰蓝--- Cloisonne

Cloisonne--- “景泰蓝” (pronounced as "Ching Tai Lan") in original Chinese, which is a special technique developed in Yuan Dynasty of China （from 1271 to 1368), and spread to other parts of the world later.

In Ming Dynasty (which is the Dynasty right after Yuan Dynasty, from 1368 to 1644), the technique had been greatly refined ---meanwhile a beautiful blue color was finally founded by the craftsmen , which turned out to be very popular, and brought the technique a worldwide reputation--- that is is why the technique is called "Ching Tai Lan" （"Ching Tai" is the name of the period when the color was found, from 1450-1456, and "Lan" means blue in Chinese）. The above information was translated from http://www.cloisonne.com.cn/, the official website of a Chinese Cloisonne Products company.

However, there is a dispution about the origin of the technique. Wikipedia still gives a search result said that "Cloisonné first developed in the Near East. It spread to the Byzantine Empire (the term conventionally used since the 19th century to describe the Greek-speaking Roman Empire of the Middle Ages, centered around its capital of Constantinople.)and from there along the Silk Road to China, now the site of many high quality production facilities."


Cloisonne

an ancient metalworking technique, is a multi-step enamel process used to produce jewelry, vases, and other decorative items. Objects produced by this process are also called cloisonné.

First, the artist forms metal (such as copper or brass) into the shape of the finished object.

A paper pattern and a pencil are used to transfer a design to the metal object.
Partitions (French: cloisons) that act as color-separators are applied according to the transferred pattern and are held in place by a soldering paste (this is finely divided metal of low melting temperature in a flux paste). The partitions are bent and cut to length from flat wire stock (usually by hand using simple pliers) while the paste is applied with a small brush.

Heating the piece in an oven permanently affixes the partitions to the base metal by melting the solder. The piece is then allowed to cool.

Frit (glass crushed to a powder) in a water-based paste is painted into the partitions using an annotated pattern similar to the "paint by numbers" craft technique. After the frit has dried, firing in an oven melts it onto the metal. Several repetitions of the process may ensue to build up the coatings to the height of the partitions. Various colors and transparencies may be used in combination within a single partition to obtain the desired artistic effect.

The glass and a portion of the cloisons are ground and polished to form an even and smooth surface.

The exposed metal is electroplated with a thin film of gold to prevent corrosion and to give a pleasing appearance.

from http://en.wikipedia.org/wiki/Cloisonne