1,5-Naphthalenedisulfonic acid, 2(or 3)-[2-[8-amino-7-[2-[5-[[4-[4-[2-[[4-[[3-[2-[1-amino-7-[2-[1,5(or 4,8)-disulfo-2-naphthalenyl]diazenyl]-8-hydroxy-3,6-disulfo-2-naphthalenyl]diazenyl]-4-sulfophenyl]amino]-6-chloro-1,3,5-triazin-2-yl]amino]ethyl]-1-piperazinyl]-6-chloro-1,3,5-triazin-2-yl]amino]-2-sulfophenyl]diazenyl]-1-hydroxy-3,6-disulfo-2-naphthalenyl]diazenyl]-, sodium salt (1:?)