Cone fundamentals and CIE standards

Abstract

A knowledge of the spectral sensitivities of the long-wavelength-sensitive (L-), middle-wavelength-sensitive (M-) and short-wavelength-sensitive (S-) wavelength-sensitive cone types is vital for modelling human color vision and for the practical applications of color matching and color specification. After being agnostic about defining standard cone spectral sensitivities, the Commission Internationale de l’ Éclairage (CIE) has sanctioned the cone spectral sensitivity estimates of Stockman and Sharpe (2000) and the associated measures of luminous efficiency (Sharpe et al., 2005, 2011) as ‘physiologically relevant’ standards for color vision (CIE, 2006, 2015). These can be used to model mean normal color vision at the photoreceptor level and postreceptorally. Both LMS and XYZ versions have been defined for 2-deg and 10-deg vision. Built into the standards are corrections for individual differences in macular and lens pigment densities, but individual differences in photopigment optical density and the spectral position of the cone photopigments can also be accommodated (Stockman and Sharpe, 1999; Brainard and Stockman, 2010). Understanding the CIE standard and its advantages is of current interest and importance.