DOES COLOUR MATCHING FOLLOW GRASSMANN'S LAWS?

摘要

We argue that, contrary to the general belief,colour matching does not satisfy two most important Grassmann's laws (transitivity and additivity). It follows that one should distinguish between metamerism and colour matching. We suggest a new definition of metamerism: lights are metameric if and only if they match the same lights. Metamerism obviously implies colour matching but the converse is, generally, not true. We also propose new axioms which colour matching should obey to guarantee the validity of Grassmann's laws for metamerism. Grassmann's laws entail the existence of colour mechanisms the equality of the responses of which amounts to metamerism. However, when colour matching is intransitive, these colour mechanisms are not linearly related to the colour matching functions. We show that the spectral sensitivities of the colour mechanisms can be derived from the colour discrimination data using the method of quadratic approximation (Logvinenko, 2003).