6. Defining the Color Stimulus

  1. Rolf G. Kuehni

Published Online: 9 OCT 2012

DOI: 10.1002/9781118533567.ch6

Color: An Introduction to Practice and Principles, Third Edition

Color: An Introduction to Practice and Principles, Third Edition

How to Cite

Kuehni, R. G. (2012) Defining the Color Stimulus, in Color: An Introduction to Practice and Principles, Third Edition, John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118533567.ch6

Publication History

  1. Published Online: 9 OCT 2012
  2. Published Print: 9 NOV 2012

ISBN Information

Print ISBN: 9781118173848

Online ISBN: 9781118533567



  • CIE colorimetric system;
  • color stimulus;
  • matching stimuli;
  • optimal object color solid


The relative “standard” stimulus can be calculated from reflectance measurements and light source spectral power distribution (SPDs) by multiplying, at each wavelength, one with the other. The determination of the relative spectral power of the light source and the spectral reflectance of the object completes the physical portion of determining the color stimulus. For a psychophysical determination of the stimulus, the physical results need to be weighted by the cone functions or in technology by the color-matching functions. In this chapter the technical system used internationally for defining color stimuli in form of lights or of light reflected from objects has been presented. It is based on determination of spectral cone sensitivity functions using the technique of metamerically matching the appearance of spectral stimuli using three lights widely separated in the spectrum.

Controlled Vocabulary Terms

colorimeters; colour vision; spectral analysis