C.I. 28440; C.I. Food Black 1, tetrasodium salt; C.I. Food Black 1; Brilliant black 1; Black PN; tetrasodium (6Z)-4-(acetylamino)-5-oxo-6-({7-sulfonato-4-[(E)-(4-sulfonatophenyl)diazenyl]naphthalen-1-yl}hydrazono)-5,6-dihydronaphthalene-1,7-disulfonate; tetrasodium (6E)-4-(acetylamino)-5-oxo-6-({7-sulfonato-4-[(E)-(4-sulfonatophenyl)diazenyl]naphthalen-1-yl}hydrazono)-5,6-dihydronaphthalene-1,7-disulfonate; Food Black 1