Madder lake contains two organic red dyes&colon; alizarin and purpurin. For example, cochineal was replaced by Spanish dyes like minium and alizarin crimson. Alizarin Red S (also known as C.I. Mordant Red 3, Alizarin Carmine, and C.I 58005. Purpurin fluoresces yellow to red under ultraviolet light, while synthetic alizarin slightly shows violet. This alizarin concentrate comprises only 1% of the madder root. Replacements are often used for chromium, cadmium and alizarin. Synthetic dyes are often derived from 9,10-anthraquinone, such as alizarin. Alizarin crimson can create a wide range of rich, permanent purples and browns. The development of this family of pigments supplanted the alizarin dyes. Anthracene is used in the production of the red dye alizarin and other dyes. Alizarin crimson paint was frequently used on Bob Ross' TV show, "The Joy of Painting". The color was then modified by treatment with an alizarin lake pigment. Diagnosis is made with arthrocentesis and Alizarin Red staining along with clinical symptoms. They are usually only detectable with an Alizarin Red S stain. Alizarin is one of ten dihydroxyanthraquinone isomers.