Coefficients of variation that show the degree to which the Hunt model of colour vision is successful in predicting the LUTCRI appearance data are gathered together in this article for a very wide range of viewing conditions. The model now consistently predicts these data as closely as the results of a single observer. agree with the average results of a group of six observers. The nature of the adjustments that have had to be made to the model to achieve this result are described. and their implications are discussed.