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18% Grey (Gray) Card

A card which has one surface a grey tone which is calibrated to be 18% reflective. This is useful to ensure exposure is correct. It is often used to calibrate the color temperature for color photography.

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18% Grey (Gray)

From tests conducted early in the development it was determined that the average scene reflects 18% of the light falling on it. Camera meters and other exposure devices use this as a standard for photographs. However, if an image is more or less reflective than this exposure compensation is required.