2-amino-1-phenol-4-sulphonic acid, 6-nitro-O-aminophenol-4-s ulphonic acid, Phenyl gamma acid (phenyl 2-amino-naphthol-6-sulphonic acid), Phenyl J acid (phenyl-2-amino-8 naphthol-7-sulphonic acid), S acid, peri acid (1-amino-8-naphthol-4-4-sulphoxinic acid, 1-naphthylamine-8-sulphonic acid), Meta-phenylene diamine-4-sulphonic acid