An essential part in digital photography process for photographers or hobbyists. With this term, there is no need for you to worry that the photos are too dark or too bright, and the color is bluish or yellow.
The grey side works for the exposure correction and white side for white balance setting. It is to provide a standard reference object for exposure determination in photography.
By placing a gray card in the scene to be photographed, oriented at a defined angle relative to the direction of the incident light, and taking a reading from it with a reflected light meter, the photographer can be assured of consistent exposures across
Gray cards can be used for in camera white balance or post processing white balance.
Provide a standard reference object for exposure determination in photography.