Surwhite S-600 is a concentrated optical brightener with blue and violet shade, which is highly substantive to cellulosic, rayon, and nylon fibers. Surwhite S-600 is particularly effective when used in a peroxide bleach bath (alkalinity, peroxide) but is not stable to chlorine. Surwhite S-600 has a high affinity to the aforementioned fibers when used in an exhaustion process.