Artists illuminating papyrus scrolls in Egypt, silk and ricepaper scrolls in the Orient, manuscripts in the Dark and Middle Ages, all worked with a water medium, usually of an opaque kind. Present-day aquarelle, often called transparent watercolor, did not evolve from these forms of painting, though. He must actually be considered the father of all Western watercolor. An important principle of transparent watercolor is never to work with white paint, which destroys the transparency, the charm of the medium. White is used in gouache as in oils.
Miniaturists often work with gouache.
This medium is pure powered pigment, compressed into small, cylindrical sticks. Recently, semi-hard pastels have been introduced. These contain a small amount of wax. The medium didn't become popular until 1775, when pastels by the Swiss artist, Jean Etienne Liotard, were shown at the Royal Academy in London. Casein Casein is an ingredient of curdled milk, used by cabinetmakers as a waterproof glue for at least eight hundred years before it occurred to someone to employ it in paint.