Color appearance: Maxwellian vs. Newtonian views

Color appearance can be studied using either Maxwellian-view optical systems or natural viewing (Newtonian-view). We show that the results are not precisely comparable when the natural pupil is appreciably larger than the entrance pupil of the Maxwellian beam. The wavelength for any given hue that is obtained from one viewing system is not the same as that obtained from the other viewing system: for the same hue, the required wavelength under Newtonian view is longer than under Maxwellian view.