The natural fluorescence of wool

Wool may be excited by both mid‐and near‐u.v. radiation, emitting fluorescence. The extent of visible fluorescence depends on the origin of the wool and the degree of weathering, (the tips of the fibres being more fluorescent than the roots) and chemical modification. In particular oxidative treatments such as chlorination of shrink‐resist procedures or peroxide bleaching processes increase the intensity of visible fluorescence but decrease the intensity of u.v. fluorescence (emission maximum at about 350 nm). It is proposed that the presence of these fluorescent chromophores in the fibre relates to the susceptibility of wool to yellow on exposure to light.