A continuing goal of color science since the establishment of the trichromatic theory of color perception [e.g., 5, 6, 7] has been the accurate determination of the spectral sensitivities of the long-, middle- and short-wavelength-sensitive (L, M and S) cones—also known as the fundamental color matching functions (or CMFs): <overline>l</overline> (λ), <overline>m</overline> (λ) and <overline>s</overline> (λ). These CMFs are the physiological bases of all other CMFs. The cone fundamentals of Stockman and Sharpe [2], which are to be recommended by the CIE Technical Committee 1-36 as an international standard for colorimetry [12], rely on measurements made in both normal trichromats and color deficient observers. These measurements are used to guide the linear combinations of the Stiles & Burch [1] CMFs that define the cone fundamentals.