Effect of 2-dimensional fluctuations in observations of colour differences

Abstract

A method of analysis of observations of colour rendering differences described in an earlier paper has been extended to take into account variability of the observations in two orthogonal directions, instead of in one only as previously. For, just as the colour differences can occur in at least two dimensions of physical colour space, so variability of observations might be expected in two dimensions of psychological space. The extended theory using the bivariate normal distribution predicts the same values of perceived colour difference as had been predicted using the univariate distribution. It also suggests that for many colours the univariate distribution is a satisfactory model for predicting the distribution of scores between categories. However, for other colours this can be better predicted if a bivariate distribution is assumed.