Botanical Name: Alizarin or madder
Alizarin, also spelled Alizarine,is  a red dye originally obtained from the root of the common madder plant, Rubia tinctorum. Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as Rose madder and Alizarin Crimson. Alizarin in the most common usage of the term and has a deep red color. Alizarin changes color depending on the pH of the solution it is in, thereby making it a pH indicator.
The application of alizarin to cotton, wool, or silk requires prior impregnation of the fiber with a metal oxide, or mordant. The shade produced depends on the metal present: aluminum yields a red; iron, a violet; and chromium, a brownish red.

Botanical Name: Alizarin or madder
Alizarin, also spelled Alizarine,is  a red dye originally obtained from the root of the common madder plant, Rubia tinctorum. Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as Rose madder and Alizarin Crimson. Alizarin in the most common usage of the term and has a deep red color. Alizarin changes color depending on the pH of the solution it is in, thereby making it a pH indicator.
The application of alizarin to cotton, wool, or silk requires prior impregnation of the fiber with a metal oxide, or mordant. The shade produced depends on the metal present: aluminum yields a red; iron, a violet; and chromium, a brownish red.