Description and Measurement of White Surfaces

This is the report of Inter-Society Color Council Subcommittee on Problem 19 formed in 1953 to study the color technology of white surfaces. Physically, surfaces which appear white reflect strongly and diffusely throughout the visible spectrum. Psychophysically, whites occupy a volume without sharply defined boundaries in the top center of the color solid. Whiteness is the attribute of white surfaces which corresponds to their visual proximity to preferred white. Preferred white varies somewhat with changes of either observer or observing situation. Measurements and intercomparisons of the colors of whites are made to determine adequacies of match to standard and to determine compliance with color specifications. One-number reflectance measurements of whites are widely used as partial determinations of whiteness. There have been a number of investigations to find which formulas yield the most reliable measurements of whiteness from tristimulus values, but the whiteness scales which have resulted from these investigations have not enjoyed widespread commercial use.