1-Naphthalenesulfonic acid, 4,5-dihydroxy-3-[(4-sulfophenyl)azo]-, disodium salt

2-Aminobenzenesulfonic acid diazo, and 4,5Dihydroxynaphthalene-1-sulfonic acid?coupling.

blue-ray red. Soluble in water for wine red, hardly soluble in alcohol. The strong sulfuric acid for dark purple, diluted red wine. In water solution to join strong hydrochloric acid for the red; Add sodium hydroxide into wine red to the deep red.

Standard	Light Fastness	Soaping		Persperation Fastness	Oxygen bleaching		Fastness to seawater
		Fading	Stain		Fading	Stain	Fading	Stain
ISO	4	2	3-4	2-3	1		3