Published online by Cambridge University Press: 30 August 2019
Zone theories of color vision transform cone sensitivities to channel sensitivities before transmitting these signals to the brain. The concepts of “unique hue” and “color opponency” are fundamental to an understanding of this transformation. Saunders & van Brakel question the objectivity of these concepts. Statements in their target article indicate that the reason for this questioning stems from a failure to appreciate the constraints inherent in the definitions of these concepts.