In the woollen system of wool production, dyeing and bleaching usually occurs in scoured loose wool form.
Dyeing wool
Although some dyeing and bleaching of woollen-spun products takes place in fabric or garment form, the vast majority of wool used in the woollen system is dyed or bleached in scoured loose wool form - prior to the carding and spinning process.
Most dyes for wool are anionic (negatively charged) in their chemical nature, and the rate of dyeing is controlled primarily by controlling both the pH and the rate in the rise in the temperature of the dye bath liquor.
The keys to successful dyeing and bleaching depends upon a combination of achieving as accurately and consistently as possible the correct shade, uniformity (levelness), meeting the colour fastness requirements, at both the least cost and damage to the environment.