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