Color space and its divisions

A synthesis of the author's recent work on color-order systems and color-di fference evaluation is provided in context of current knowledge and practic es. The development of a colorimetric model is demonstrated using Munsell " Celtic crosses" as a model of perceptual space. Issues surrounding color-ma tching functions, unique hues, the Helmholtz-Kohlrausch effect, and lightne ss and chroma crispening are addressed, as is the difficulty of reconciling a difference-based hue, chroma, lightness model with an Euclidean model. A new lightness scale and treatment of lightness crispening is proposed The results indicate that, despite problems, relatively simple modified opponen t-color models provide good accuracy in predicting color-order system and s upra-threshold small color-difference data. (C) 2001 John Wiley & Sons, Inc .