Bluette functions as a laundry whitener because a trace of blue in the wash will enhance white and light-colored articles, making them appear whiter and brighter. It works because of an optical illusion called irradiation. Try Bluette for whiter whites. It is safe and gentle even on delicate fabrics. Laundry bluing is added to the detergent at the start of the wash cycle - unlike other laundry products that are added during the final rinse cycle.