Rose madder is a red paint made from the pigment madder lake, a traditional lake pigment extracted from the common madder plant Rubia tinctorum.
Rubia tinctorum, from whose root the colour is extracted
A lake pigment is a pigment made by precipitating a dye with an inert binder, or mordant, usually a metallic salt. Unlike vermilion, ultramarine, and other pigments made from ground minerals, lake pigments are organic. Manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the dyes involved are not lightfast. Red lakes were particularly important in Renaissance and Baroque paintings; they were often used as translucent glazes to portray the colors of rich fabrics and draperies.
Titian used glazes of red lake to create the vivid crimson of the robes in The Vendramin Family Venerating a Relic of the True Cross, c. 1550–60 (detail).