The article examines the concepts of the following three quantities: partial colour sensitivity of a recipe to a particular colorant, colour balance of a recipe, and the over-all colour sensitivity and the related property of colour robustness of a recipe. The way to calculate numerical estimates of the above quantities is extended from the case of CIE L*a*b* to the case CMC(l:c) colour difference formula. Results of a few numerical experiments are included for illustration and some possible practical consequences are discussed.