title: Direct-reading color-difference meter based on cube-root color coordinates.
abstract: This paper describes a new instrument, based on the cube-root system of color coordinates, which reads color-difference coordinates directly. Silicon photovoltaic cells are used with glass filters to produce electrical signals proportional to tristimulus values. Tristimulus signals from a reference and a sample are converted to coordinate differences by means of simple, solid-state circuitry. Because operation of the instrument requires no mechanical adjustment or data entry, a color difference can be measured in about 15 sec. Excellent precision and stability have been demonstrated.
authors.forename: M E
authors.initials: ME
authors.lastname: Faulhaber
authors.forename: P G
authors.initials: PG
authors.lastname: Witherell