disodium 4-amino-3-[[4-[(2-amino-4-hydroxyphenyl)azo]phenyl]azo]-5-hydroxy-6-(phenylazo)naphthalene-2,7-disulphonate;Direct Black 155;Direct Black BF;2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4-[(2-amino-4- hydroxyphenyl)azo]phenyl]azo]-5-hydroxy-6-(ph