ISO 18314-3:2022 specifies how to calculate special indices for Color samples. These indices are used to describe the luminance of the sample, the luminosity, and the hue within a specific chroma coordinate. The standard applies to samples using the CIE 1931 (2 °) or CIE 1964 (10 °) standard Colorimetric systems. Compared to the previous version, the new version removes the relevant clauses for relative black values and relative gray values, updates the terms and definitions, and adds new references. The standard provides a method for accurately describing Color stimuli with one-dimensional values, suitable for Color measurement of reflection or transmission objects.