Aspects of the Photobleaching and Photoyellowing of Wool

The photobleaching of wool, using the 488 nm line of an argon ion laser and north light fluorescent lamps, in wet and dry states, has been studied. Destruction of the chromophores absorbing in the visible region was accompanied by a modest increase in UV-absorbing chromophores. Use of north light lamps resulted in little change in the natural fluorescence, whereas irradiation with the 488 nm laser line caused a decrease. UV irradiation of wool using either the 351 nm line of the argon laser or UV fluorescent lamps led to exhaustive yellowing, manifested by an increase in both visible-light- and YV-absorbing chromophores, and this was generally accompanied by a marked increase in natural fluorescence. The wool yolk has a definite protective effect upon UV irradiation of wool but no effect was observed upon north light irradiation