Colorimetry: How To Measure Color Differences

By Randy Klimek, Project Manager

Colorimetry, the science of color measurement, is widely employed in commerce, industry and the laboratory to express color in numerical terms and to measure color differences between specimens. Applications include paints, inks, plastics, textiles and apparel, food and beverages, pharmaceuticals and cosmetics, displays, and other parts and products that reflect or transmit color.

The use and importance of colorimetry has grown in unison with the increase of global manufacturing and processing. When plastic automotive trim produced on one continent, for example, must match a painted metal finish applied on another, an objective and precise description of color becomes an absolute necessity.

Unfortunately, human color perception varies widely and is affected by illumination, sample size, surrounding color and the angle of observation. Colorimetric instruments provide a set of standardized conditions that help assure consistency and repeatability.

While the term colorimetry often is used in a general sense to mean color measurement, it differs from spectrophotometry, a related but distinct method of color measurement.