Also known as the Kodak neutral test card, a gray card is an 8 X 10 (20 cm by 25.5 cm) card, about 1/8 thick, that is uniformly gray on one side. The gray side reflects precisely 18% of the white light that strikes it (corresponding to the calibration of a reflected-light meter). It is uniformly white on the other side, which reflects 90% of the light.Photo Tips
Another name for a neutral density filter, or ND filter.
The range of tones, from bright white to pitch black that can be reproduced in a film and print.
A commercially prepared card that reflects 18 percent of the light hitting it. Visually it appears neutral, or a middle gray halfway between black and white.
neutral card that is helpful for measuring light and leads to consistent exposures.
A Matte 18% reflectance card used instead of a subject for a Reflected Light Meter reading. Tips: Exposure corrections for unusually light or dark subjects are the same as for an ILM - not an RLM. Angle the card for typical but glare-free light. See: 18% Assumption.