Colorimetry Tutorial

The purpose of this paper is to give a brief overview of colorimetry. Colorimetry is the science of measuring color and color appearance. The main focus of colorimetry has been the development of methods for predicting perceptual matches on the basis of physical measurements. This topic is much too broad to be covered by one document, so a general coverage of the subject will be introduced.

The question of what is color would seem to be an easy one at face value. If a child was asked what color an apple was, they would say red. But what does red really mean? Most people have been asked the riddle, "if a tree falls in the forest and no one is there to hear it, does it make a sound?" The answer is it makes a sound wave, but it is not a sound until a brain interprets the sound wave. The same can be said if the riddle asks, "what color is a tree if no one is there to see it?" A 'color' is an interaction between a very small range of electromagnetic waves and the eyes and brain of a person. What people call red, green, or blue are just ways of categorizing what their brain experiences.