Lisebelisoa tse khanyang li boetse li bitsoa li-optical brightening agents kapa fluorescent whitening agents. Tsena ke metsoako ea lik'hemik'hale e monyang khanya sebakeng sa ultraviolet sa mahlaseli a mahlaseli a kotsi a motlakase; tsena li boetse li hlahisa leseli sebakeng se putsoa ka thuso ea fluorescence