The number of discernible colours

Abstract

How many colours can the eye distinguish? The published literature is remarkably inefficient at providing an answer to this important question. An often quoted reference states that "10 million surface colours can be distinguished by the normal human eye under optimum observing conditions." Unfortunately, the authors fail to provide any further information as to the origin of this figure. This short contribution describes some of the historical attempts at answering the question, and then suggests a realistic solution. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 52–54, 1998