Objective measurement of colour in naturally pigmented wool : a thesis submitted for the degree of Master of Applied Science (Animal Science) at Massey University, Palmerston North, New Zealand

Abstract

This thesis examines some issues important in considering production of naturally-pigmented wools in New Zealand. Major wool characteristics are reviewed in terms of processing requirements. Statistics of New Zealand production of naturally-pigmented wools are limited, as are data relating to the number and colour of black and coloured sheep farmed in New Zealand. Objective measurements are not widely used by the wool growers; in addition, the lack of a recognised colour standard for these wools limits the marketing of sale lines. The major characteristics of black and coloured wool samples sourced from three regions of New Zealand were analysed and presented. In the absence of a colour standard, tristimulus values (XYZ) and CIELAB (L*a*b*) values were measured using a spectrophotometer. The CIELAB scale provided better distinctions between black, brown and grey wools which had been subjectively graded into categories labelled 'light', 'medium', 'dark', and 'moorit'. CIELAB values for each colour grouping are proposed. To meet the requirements of wool processors, sheep breeders need to supply wools to specification. Wool production objectives are discussed in line with selection objectives, selection criteria and selection methods. The linkages between farmers and processors are reviewed in the light of existing New Zealand practices. The role of the Black and Coloured Sheep Breeders' Association of New Zealand, wool buyers, wool brokers and auction houses is examined In view of the limited quantity of naturally pigmented wools available in commercial (>500kg) quantities, the study suggests that the Association introduce a brand name for the wools produced by its members and establish one sale location only as a means of raising quality standards and the availability of marketable quantities.