1,5-Naphthalenedisulfonic acid, 3,3'-[carbonylbis[imino(2-methyl-4,1-phenylene)azo]]bis-, tetrasodium salt 3214-47-9 C.I. Direct Yellow 50 C.I. Direct Yellow 50, tetrasodium salt Direct Fast Yellow R Direct Lightfast Yellow K Direct Yellow 50 NSC47763 Sirius Light Yellow R Sirius Light Yellow R Extra