UNE-EN ISO/CIE 11664-3:2020

This document specifies methods of calculating the tristimulus values of colour stimuli for whichthe spectral distributions are provided. These colour stimuli can be produced by self-luminous lightsources or by reflecting or transmitting objects.This document requires that the colour stimulus function be tabulated at measurement intervals of5 nm or less in a wavelength range of at least 380 nm to 780 nm. Extrapolation methods are suggestedfor cases where the measured wavelength range is less than 380 nm to 780 nm.The standard method is defined as summation at 1 nm intervals over the wavelength range from 360 nmto 830 nm. Alternative abridged methods are defined for larger intervals (up to 5 nm) and shorterranges (down to 380 nm to 780 nm). The alternative methods are to be used only when appropriate andwhen the user has reviewed the impact on the final results.This document can be used in conjunction with the CIE 1931 standard colorimetric observer or theCIE 1964 standard colorimetric observer.