The Douglas Grey Card combines trusted scientific principles with new materials to provide better colour balancing of digital and conventional materials, for the fullest range of natural and artificial light conditions.

The card reflects the same proportion of all colours of light falling on it, including ultra-violet and the limit of visible red. It has a more neutral reflectance than rival products under the widest range of sources of illumination, including tungsten, daylight, flash and warm fluorescent tubes.

Manufactured in a tough synthetic it can be written on with a Chinagraph pencil or marker designed for wall planners, and cleaned off with a mild detergent or a spray cleaner designed for cleaning TV or computer screens.

Folded, the Douglas Grey Card is just under A5 size (9" x 7" / 225mm x 175mm) to fit snugly in your camera bag. Fully opened it is large enough to fill a 35mm camera viewfinder at 50 cm/1 ft 6 ins with a 50mm lens. The grey side has a reflectance value of 18% which represents a middle value of 5 in the Munsell system of colour notation and the middle tone (Zone V in the Ansel Adams Zone System) used for exposure determination, half way between pure black and pure white. The grey side is used for exposure measurement for either digital, negative or colour transparency material, for colour balancing and for the setting of white balance. The white side is used for measuring lighting contrast and as a superior method of exposure measurement for colour transparency material.