The ColorChecker Gray Scale Card from Xrite is a full-size version of the white, 18% gray and black reference square used in the standard 24-patch ColorChecker. This target is scientifically engineered to provide a precise uniform surface that is spectrally neutral (reflects equal amounts of red, blue and green) in all types of light conditions. Photographers can use the ColorChecker Gray Scale as the first reference shot in a series to easily correct image color under most lighting conditions by balancing on the mid tone gray value.
For the studio photographer, the X-Rite ColorChecker Gray Scale lets him or her quickly set up the proper studio lighting ratio between main and fill lights for capturing accurate color with a minimum of after-the-fact manipulation.
In addition, the ColorChecker Gray Scale provides reference values that can quickly be checked and used to adjust colors within most common photo processing software packages.