When in the above formula, R1 is anilino, R2 is N-2-hydroxyethyl-N-2-methylamino and M is a cation such as sodium, the brightener is 4,4'-bis (4-anilino-6-(N-2-hydroxyethyl-N-methylamino)-s-triazine-2-yl)amino!2,2'-stilbenedisulfonic acid disodium salt.