1,3'-Bipyridinium, 5'-[2-(3-aminophenyl)diazenyl]-1'-[3-(dimethylamino)propyl]-1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-, chloride, hydrochloride (1:1:1), diazotized, coupled with diazotized 5'-[2-(4-aminophenyl)diazenyl]-1'-[3-(dimethylamino)propyl]-1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-1,3'-bipyridinium chloride hydrochloride (1:1:1) and resorcinol