Rublev Colours Pigment Alizarin Crimson - 4 oz

The roots of the plant Rubia tinctorum supply the colouring substances that are converted to madder lakes, the principal colouring substance which is alizarin.

Alizarin crimson is a synthetic lake pigment based on the dye alizarin precipitated onto aluminum.

Pigments and dyes are not identical, although there are cases in which the same colouring matter which yields a dye or stain may give rise to a pigment. A pigment is, in fact, a substance which is insoluble in the vehicle with which it is mixed to make a paint, while a dye is soluble. A lake pigment is a natural organic pigment prepared when a dye has been precipitated on a powdered, colorless, inorganic substrate. The term derives from the Latin word lacca, used in the Middle Ages to denote both lake pigments and the Lac dye. Because of its transparency, aluminum hydroxide is the most commonly used substrate or carrier. Barites, such as barium sulfate, provide an opaque lake pigment. Other compounds used as carriers are: chalk, clay, gypsum, tin oxide, zinc oxide, white earth, and green earth. Often a mordant, such as tannic acid, lactic acid, or sodium phosphate, is used to fix the dye to the substrate. Madder lake and rose madder for artists' pigments are prepared from madder extract by adding alum and precipitating with an alkali.

Warning: the pigment alizarin crimson is considered to be non-toxic but care should be taken not to inhale the dust when preparing paints.