Does extending the number of channels from the 3 RGB sensors of a colour camera to 6 or 9 using a multispectral camera enhance the performance of illumination-estimation algorithms? Experiments are conducted with a variety of colour constancy algorithms (Maloney-Wandell, Chromagenic, Greyworld, Max RGB, and a Maloney-Wandell extension) measuring their performance as a function of the number of sensor channels. Although minor improvements were found with 6 channels, overall the results indicate that multispectral imagery is unlikely to lead to substantially better illumination-estimation performance.