Shale yellow
The Schüttgelb is a pigment of historical importance produced by laking vegetable dyes onto a mineral substrate . It was used as a glaze in panel painting in the Middle Ages . It was bound in glue , more rarely in oil , and was used as a pastel by painters until the 19th century . It is not lightfast.
Other well-known names (nicknames) for Schüttgelb are Gelber Lack and Stil de grain ( Stil de grain brun , Stil de grain vert ), English dutch pink , persian berry lake or buckthorn pibment . The traditional name Schüttgelb only refers to a pale yellow shade today.
The coloring part mostly came from the dried berries (yellow berries) of the buckthorn species (genus Rhamnus) - buckthorn berries . These are the ingredients rhamnetin ( C 16 H 12 O 7 ), a methyl ether of a pentahydroxyflavone , as well as rhamnazine and quercetin .
Buckthorn berries can be used to produce pigments of various shades: unripe berries turn yellow, ripe berries turn green and overripe berries turn purple-red.