What Are Tristimulus Values?
Tristimulus values measure the light intensity of the primary color values in a sample. The name is derived from the three (tri) primary color values (stimuli) measured. Tristimulus values express the color and visually perceived reflectance. They are essential for color language because these measurements communicate precise color values without human objectivity.
These results are obtained from a tristimulus system. This system visually matches colors against red, green, and blue under standardized conditions to mimic how the human eye sees. The three results are expressed as X, Y, and Z coordinates on a graph. The Y value represents the sample's luminance, and the X and Y values together represent the sample's chromaticity.
What Is the CIE Color Model?
The Commission Internationale de l'éclairage (CIE) color model is a color space model that accurately represents every color perceivable to the human eye. The CIE color model plots tristimulus values on a 3D space, which create a unique color when combined.
With the CIE color model, colors can be accurately expressed, communicated, and reproduced. Though this model takes the chromatic response of the eye into account, this model is not intended to describe color with qualities such as saturation or hue.