The colour of scoured wool ranges from a very bright white to a dull yellow/orange. For wool where all characteristics except colour are equal, the higher the prices are invariably paid for the whitest wools.

There is a weak relationship between greasy and scoured wool colour. Hence it is difficult to predict scoured wool colour by visual assessment of the greasy fleece. Therefore it is critical for any purchaser to objectively test the colour of wool.

The following values, in D65/10 degree colour space are given as an indication of the range of the Yellowness Index for wool.

Colour description	Y-Z units (Yellowness index)
Very white	< 8
White	8-11
Creamy (off white)	11-16
Yellow	>16