Colours applied in enamelling that are fixed in a muffle furnace. Enamel colours are metallic oxides mixed with a frit of finely powdered glass. When used for painting, they are suspended in an oilmedium for ease of application with a brush, the medium burning out during firing. The actual colours develop in the kiln. Enamel colours were originally opaque (owing to the inclusion of tin),but in the 17th century a transparent enamel was develop, and it is the variety most often used on enamelled jewelry.
Enamel Colors

Enamel Colors
Colours applied in enamelling that are fixed in a muffle furnace. Enamel colours are metallic oxides mixed with a frit of finely powdered glass. When used for painting, they are suspended in an oilmedium for ease of application with a brush, the medium burning out during firing. The actual colours develop in the kiln. Enamel colours were originally opaque (owing to the inclusion of tin),but in the 17th century a transparent enamel was develop, and it is the variety most often used on enamelled jewelry.
References
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson



