Rubia is a genus of climbing, flowering plants of the Rubiaceae family. The genus includes approximately eighty species that derive originally from Eurasia. Among these plants are Rubia argyi (East Asian madder), Rubia cordifolia (Indian madder), Rubia peregrina (wild madder) and Rubia tinctorum (common madder), all of which can be used to produce red dyes, although the most widely used is Rubia tinctorum.
The red colour is derived from an organic compound called alizarin, which can be found in varying degrees of concentration in the roots. It is a substantive dye (no mordants are needed), although it is necessary to have high levels of chalk (‘hard water’) in the water in order to obtain a satisfactory colour. The use of madder was more or less replaced in the twentieth century by a synthetic anthracene compound, also called alizarin.
Sources:
- CHENCINER, Richard (2000), Madder Red: A History of Luxury and Trade, London: Routledge.
- TORTORA, Phyllis G. and Ingrid JOHNSON (2014). The Fairchild Books: Dictionary of Textiles, 8th edition, London: Bloomsbury, p. 367.
- Shorter Oxford English Dictionary: ‘Madder’.
Digital source of illustration (retrieved 7th July 2016).
GVE