12227-81-5 69073-21-8 73904-83-3 8005-03-6 Acid black 2 C.I. Acid Black 2 CI 50420 CI Acid black 2 Calco nigrosine O 2P HSDB 1971 Lurazol Deep Blue EB NIGROSINE Nigrosin Nigrosine B Nigrosine WSB Nigrosine wl water soluble