This document specifies methods of calculating the tristimulus values of colour stimuli for which the spectral distributions are provided. These colour stimuli can be produced by self-luminous light sources or by reflecting or transmitting objects.
This document requires that the colour stimulus function be tabulated at measurement intervals of 5Ânm or less in a wavelength range of at least 380Ânm to 780Ânm. Extrapolation methods are suggested for cases where the measured wavelength range is less than 380Ânm to 780Ânm.
The standard method is defined as summation at 1Ânm intervals over the wavelength range from 360Ânm to 830Ânm. Alternative abridged methods are defined for larger intervals (up to 5Ânm) and shorter ranges (down to 380Ânm to 780Ânm). The alternative methods are to be used only when appropriate and when the user has reviewed the impact on the final results.
This document can be used in conjunction with the CIEÂ1931 standard colorimetric observer or the CIEÂ1964 standard colorimetric observer.