In ceramics, enamels may be applied either to a pre-fired, unglazed body, or painted onto the surface of a high-fired glaze, after which the object is fired a second time at a lower temperature. Overglaze enamels seem first to have appeared in China on stonewares made at the Cizhou kilns in the Song or Jin dynasties.
Enamel pigments in its natural state is a dry powder. It can be applied in several ways, usually mixed with oil, glue or plain water. When applied by painting, the colors are applied by gently, sweeping brush strokes. Once the pigment has dried no further work can be done without first firing the ware. If another color is to be painted over the first coat it is sometimes necessary to keep the applied oxides wet. If the initial coat was allowed to dry it would be removed by the brush when the second coat was applied.
By incorporating an extender into the color paste the mix is kept wet for a longer period. Substances commonly used in the west include eucalyptus, oil of cloves, lavender and anis turpens (a derivative of aniseed).
Temporary outlines can be used on the ware to guide the decorators, which later burns away in the firing. In China printed transfers have recently come into use for outlines and borders, and from around the 1970's for entire decorations.
Certain Chinese enamel decorations or palettes are recognized by western or Chinese made-up names which have resulted in a considerable confusion, since they more often than not overlap each other. Examples of such names are wucai, doucai, fencai, yingcai, sancai, susancai, famille verte, famille noire, famille jaune and famille rose.
Falangcai is an early term referring to enamel decoration on porcelain. Falang is likely to be a corruption of the word "foreign". Although still a topic of scholarly debate, the term falangcai is usually applied to the particularly fine enameled decorated in the imperial workshops of the palace in Beijing, using the fully developed famille rose/fencai palette. The application of the enamels on these porcelains is very sophisticated and the pictorial decoration is often accompanied by a calligraphic inscription in black enamel and imitations of seals in pink enamel. In the past such enamels have also been known by the name Guyuexuan (Ancient Moon Studio).
Famille verte is nowdays recognised as the French term for a Kangxi period version of wucai (five color decoration) and after the invention of the overglaze blue enamel was added to the late Ming wucai palette, and where shades of green are the dominant colors. Looking back at the origins of the name, it is a little bit more complicated than that and the concepts becomes contradictory, so lets not go there.
With the introduction of the rose enamel in the last years of the Kangxi reign, a new color palette is developed in the Yongzheng period with the addition of lead arsenate to the enamels creating new opaque colors (not translucent) which became known as the Famille Rose. The mixture of white made the Chinese use the word ruancai, meaning soft colors to distinguish them from the translucent clear and brilliant Famille Verte palette of "hard colors" yingcai. As an example, the Tang dynasty "three color" (sancai) decoration is "hard colors".
During the Qianlong period the same fully developed color palette (Famille Rose) was known as yangcai also with the meaning "foreign colors", but not from the Imperial workshop. In the 19th C the name changes yet again to fencai meaning "powdery colors" on a white ground. The three terms used to describe the famille rose palette at different times then are ruancai, yangcai, and finally fencai.
Even if these explanations are not perfect, they are at least pretty close.