Madder (Rubia tinctorum, also called garance) is a plant, whose root contains a certain number of coloring molecules going from orange to purple, passing through red. The most famous of these ones is alizarin, which was also one of the first colors to be sintesized in laboratory. The other coloring principle is purpurin, which has a lower fastness than alizarin. The color extracted from madder owns a good fastness within the plant based ones: lake pigments prepared from this root have been used during the centuries by painters for their beauty too. Since it is an alumina lake, its covering power is not high, but it owns a great transparency and brilliance. It is therefore more suitable for watercolors than for oil painting. It's particularly apt for its use in watercolors, but it's also really good for glazing in oil colors.
Compatibility: Madder lake will decompose if it's used together with lime (for example in fresco). Raw earths can fade it; this doesn't happen with calcined ones (or burnt ones). It fades with some chemical colors like zinc oxide, lead whits, Naples yellow, chrome yellow and green yellow, while it's stable with other pigments like cadmium yellow, vermilion and carbon black.
Use: In fine arts mostly for the preparation of watercolors and temperae. It is also suitable for oil painting, especially for glazing.