Visual Colour Shades in Pelts from Brown Mink (Mustela vison) Explained Colourimetrically

Microspectrophotometric methods were used to provide objective correlates to the visually judged colour shade (CS) of the underfur in scanbrown mink pelts. The study included 21 scanbrown mink pelts (winter coat), representing a larger group of 87 mink pelts coming from a feeding trial with experimental and control animals. The pelts were visually graded from 1 (blue-greyish) to 5 (reddish), primarily in respect of the CS (in auction classification=clarity of colour) of the underfur seen on the edge of the pelt. Prepared samples of underfur fibres showed in visual inspection a gliding change of colour from paler to darker in a proximal-distal direction and were consequently examined at three levels above the skin surface. The means of the dominant wavelengths (hues) were 589.40, 588.00 and 586.70 nm, respectively, indicating that the variation between levels was small. Investigation of the small pelt material concerned showed that CS was significantly correlated with the measured lightness (L*) and with the yellow chromaticity coordinate (b*) of the underfur samples. In this investigation it was also shown that the underfur fibres with a visually blue-greyish colour shade were relatively dark and less yellow compared with underfur fibres with a reddish colour shade. However, data and the model estimating the colour shade demonstrated that, for the material concerned, visually very reddish underfur colour shades were not found in the lightest coloured pelts.