C.I. Pigment Red 57, disodium salt; C.I. Pigment Red 57 (7CI); C.I. Pigment Red 57, disodium salt (8CI); D & C Red no. 6; disodium (4E)-4-[(4-methyl-2-sulfonatophenyl)hydrazono]-3-oxo-3,4-dihydronaphthalene-2-carboxylate; disodium 3-hydroxy-4-(4-methyl-2-sulfonato-phenyl)azo-naphthalene-2-carboxylate