Synonyms: 1H-Indole-5-sulfonic acid, 2-(1,3-dihydro-3-oxo-5-sulfo-2H-indol-2-ylidene)-2,3-dihydro-3-oxo-, sodium salt (1:2), 1H-Indole-5-sulfonic acid, 2-(1,3-dihydro-3-oxo-5-sulfo-2H-indol-2-ylidene)-2,3-dihydro-3-oxo-, disodium salt (9CI), C.I. Acid Blue 74 (6CI), [?2,2'-Biindoline]-5,5'-disulfonic acid, 3,3'-dioxo-, disodium salt (8CI), 12070 Blue, 1311 Blue, 5,5'-Indigodisulfonic acid disodium salt, A.F. Blue No. 2, Acid Blue 74, Acid Blue W, Acid Leather Blue IC, Airedale Blue IN, Amacid Brilliant Blue, Aniline Carmine Powder, Ariavit Indigo Carmine, Atul Indigo Carmine, Basovit Blue 665E, Blue 2, Blue No. 2, Bucacid Indigotine B, C.I. 73015, C.I. 75781, C.I. Food Blue 1, C.I. Natural Blue 2, Canacert Indigo Carmine, Carmine Blue, Carmine indigo, Cilefa Blue R, Cogilor Blue 511.11, Disodium 5,5'-indigodisulfonate, Disodium 5,5'-indigotin disulfonate, Dolkwal Indigo Carmine, E 132, Edicol Supra Blue X, Eurocert Indigo Carmine 311811, FD & C Blue 2, FD & C Blue No 2-307045, FD and C Blue 2, FD and C Blue No. 2, FD&C Blue No. 2, FD&C Blue No. 2-37006, Food Blue 1, Food Blue 2, Food Blue No. 1, Food Blue No. 2, Grape Blue A, HD Indigo Carmine, HD Indigo Carmine Supra, Hexacert Blue No. 2, Hexacol Indigo Carmine Supra, Indigo Carmine 307019, Indigo Carmine 36009, Indigo Carmine 37006, Indigo Carmine A, Indigo Carmine AC, Indigo Carmine BP, Indigo Carmine Conc. FQ, Indigo Carmine Powder, Indigo Carmine X, Indigo Extract, Indigo carmine, Indigo carmine 85E132, Indigo carmine E 132, Indigo carmine NB, Indigotin, Indigotin (solubilized), Indigotine, Indigotine B, Indigotine Blue LZ, Indigotine Carmine, Indigotine Extra Pure A, Indigotine I, Indigotine IA, Indigotine Lake, Indigotine N, Indigotine disodium salt, Indocarmine F, Intense Blue, Japan Blue 2, Japan Food Blue No. 2, L Blue Z 5010, Maple Indigo Carmine, Mitsui Indigo Carmine, Necol Indigo Carmine, Neelicol Indigo Carmine, San-ei Indigo Carmine, Sepisperse Dry 1003, Sodium 5,5'-indigodisulfonate, Sodium 5,5'-indigotindisulfonate, Soluble indigo, Soluble indigo blue, Sumitomo Wool Blue SBC, Usacert Blue No. 2, Usacert FD & C Blue No 2-310118, Usacert FD and C Blue No. 2, WAS 35, Water Blue 177557, Water Blue 177558, Indigo carmine, Indigotindisulfonate sodium