Although color measuring instruments are widely used, color matches are usually checked visually. The standardization of visual examination has greatly improved the uniformity of products and the accuracy of color matches.

The use of this practice is essential for critical color matching but is also recommended for any color appraisal, such as the choice or approval of a color. This practice is widely used in industry to choose colors, exhibit colors reproducibly, inspect incoming materials, monitor color producing processes, and inspect finished goods. Visual appraisal is particularly important when the product inspected is not of the same material as the color standard to which it is compared.

Observers-This practice is based on the fundamental assumption that the observer has normal color vision and is trained and experienced in observing and classifying color differences. The significance of the results depends on that being so. The selection, evaluation, and training of observers are treated in Guide E1499.

Illumination-Simulated average daylight is recommended by the International Commission on Illumination (CIE), but a slightly bluer simulated north-sky daylight came into widespread use in North America, because it provides a slightly greater distinction between very pale yellow and white, a distinction of great commercial importance.