A flat, light-gray target engineered to reflect exactly 18% of the light that hits it. This value represents the average visual reflectance of a natural scene, serving as the universal reference standard for camera light meters.
- Primary Function: In digitizing and photography, light meters assume every scene averages out to middle gray. Photographing an 18% gray card alongside originals allows creators to achieve accurate exposure and set neutral color temperature (white balance) without guesswork.