An optical brightener mixture for preparing brightened polyamide and/or polyurethane fibers possessing improved washfastness for the optical brightening comprising A) at least one anionic brightener selected from the group consisting of derivatives of pyrazoline that bear sulfonic acid or sulfonate groups and such anionic brighteners as are reproduced in formulae 1 to 12, and B) at least one anionic brightener comprising at least a 1,2-stilbene derivative that bears a sulfonic acid or sulfonate group on each phenyl group of the 1,2-stilbene and is substituted by a nitrogenous aromatic heterocycle at each phenyl group of the 1,2-stilbene. |