A Colorimeter is designed to perform a type of psychophysical sample analysis by mimicking human eye-brain perception, which means its measurements correlate to human perception.. In other words, it is designed to see color the way we do.
Its results are direct and read as tristimulus values. A tristimulus value is one that identifies a color with characters that represent different dimensions of its visual appearance. A tristimulus value may contain values like X, Y and Z or L, a and b. The “gold standard” for tristimulus colors is the CIE Color System, developed by the International Commission on Illumination — the CIE in the title stands for the French version of their name.