Changes in Wool Colour. Part I: Incubation of Wool to Promote a More Stable Wool Colour

Abstract

Nine lots of wools representing a wide range of types were selected in order to study changes in wool colour during storage. Core samples from each bale in the 9 lots were measured for clean colour both before and after incubation for one week at 40°C and 100% RH in a water bath. The colour of wools which were resistant to yellowing changed little from their original, non-incubated clean colour, while susceptible wools deteriorated to a more stable colour. Wools which were yellow before and after incubation had higher pH and potassium contents. The change in colour of clean wool following incubation was on average one third of the increase in colour after a greasy wool incubation. The clean colour of wools after incubation in the greasy state at 55°C for 16 hours was similar to the clean colour after a blank dyeing. Clean colour measurement after incubation could form the basis of a discoloration propensity test method for certification purposes.