The reduction of disulphide bonds in wool by tri-n-butylphosphine enhances the fluorescence. Subsequent S-alkylation also affects the fluorescence intensity and charge in the neighborhood of the chromophoric group. In acylation of wool, short-chain and bifunctional acylating agents exert a greater quenching effect on the fluorescence than do long-chain alkylating agents. Esterification of wool is accomplished by an increase in fluorescence, the effect decreasing as the size of the esterifying alcohol is increased. Dilute acid also enhances the emission, but prolonged treatment, increased acid concentration -- AATA