Wool processing

Dyeing

Wool can be dyed after scouring (termed stock dyeing), after spinning (hank dyed or cone dyed) or after the fabric or garment has been made (piece-dyed).

Until the middle of the 19th century, dyes were obtained from shellfish, the crushed bodies of insects, the bark of trees, the juices of berries and fruit, and other natural sources. The first synthetic dye, made from coal tar, was made in 1857. Today, most dyes are petroleum derivatives, and there are around 6,000 altogether.

Wool dyes easily. It will readily absorb a wide range of dyes, from pastel colours to the deepest shades. Dyes are normally applied to the fibre in a water solution. Heat is important in the process and wool is normally dyed at boiling point or near boiling point.

Dyeing is both an art and a science. Often the dye-master in a mill will have to dye large quantities of wool over several batches, to exactly the same shade. They may often have to create the exact same shade with a different batch or blend of wool at a later date.