4-Amino-3-[[4'-[(1-hydroxy-4-sulfo-2-naphtyl)azo]-3,3'-dimethyl-1,1'-biphenyl-4-yl]azo]-1-naphthalenesulfonic acid disodium salt

3,3′-Dimethylbenzidine double nitriding, first with 4-Aminonaphthalene-1-sulfonic acid matches, again with 4-Hydroxynaphthalene-1-sulfonic acid coupling. In some brands are available in 6-Aminonaphthalene-1-sulfonic acid instead of 4-Hydroxynaphthalene-1-sulfonic acid.

dark red light purple. Soluble in water for Red sauce, soluble in ethanol for product Red. The strong sulfuric acid for blue, blue for red after diluted. The dye solution to join strong hydrochloric acid for hidden cyan, have precipitation; Add thick sodium hydroxide solution for red wine.

Standard	Acid Resistance	Alkali Resistance	Light Fastness	Soaping		Water
				Fading	Stain	Fading	Stain
ISO	1	3	2	1-2		1-2