It's a minor point, but I ran across this site that states we've been using the wrong name for the process that makes our C-pillar badges.
These enameled emblems are often, incorrectly, referred to as cloisonné. Cloisonné is an enamel process in which separate bands of metal are bent then applied to a base. These labor intensive bands encase the enamel and create the design. I have yet to see an automobile emblem done with cloisonné. The process that is used is called champlevé (pronounced shomp´-leh-vay).
The champlevé technique involves applying enamel into depressions in the base metal. These depressions may be etched, engraved or, in the case of automobile emblems, die stamped. The stamping process can also include the beautiful design work that shows under transparent enamels.
Historically the word enamel meant glass but today it seems to refer to any shiny color. The correct terminology is vitreous [glass] enamel. It is a true glass that melts and fuses around 1400 degrees F.
Enamel can be obtained as opaque, translucent or transparent. The colors are created by the addition of metallic oxides to the glass. The most common form is ground to #80 mesh and looks like colored granulated sugar. These enamels are formulated to molecularly bond with copper, silver and gold.