Technics used by Jean Cocteau

The enamel

Jean Cocteau prefers to use enamel to underline a detail (red spot on the eyes) or for the traits. Only some examples have enamelled backgrounds.
Théâtre du Cap d’ail

The pencil made out of oxides

In 1958, nothing of the sort exists in the French pottery ; Jean Cocteau invented this pencil to give his designs an appearance of pastel. It consists of a mixture of pasty clay and oxides rolled by hand into linttle cylinders like a pastel that will be used, after drying, like a pencil. This technique was rather empirical.
Orphée et Eurydice
Orphée à la lyre

The slip

Liquid clay called "Barbotine" to which metallic oxides are added, giving it its colour during the baking process. The mixture is applied on the surface of a piece of unfired clay. The slip can re-cover the piece to make a background or can be re-engraved to find the initial colour of the piece.
Atalante et Hippomène