Studies in Wool Yellowing

Abstract

Wool and silk fabrics which have been exposed to light of wavelengths present in sunlight undergo further changes in yellowness on treatment with water. Depending upon the wavelengths of the initial radiation, wetting may cause either bleaching or yellowing. For wool fabrics irradiated at 310 nm, wetting initially produces bleaching followed by yellowing, whereas fabrics irradiated at 365 nm are either yellowed or bleached depending on whether or not the sample is fluorescent-brightened. At wavelengths greater than 390 nm, only yellowing is observed. The effect of oxygen on the photoyellowing of wet fluorescent-brightened wool and silk has been examined.