Cuprate(4-),[4-amino-5-(hydroxy-kO)-6-[2-[2-(hydroxy-kO)-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl-kN1]-3-[2-[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-2,7-naphthalenedisulfonato(6-)]-,hydr