A gray card is a neutral reference surface (usually 18% gray) used in photography and filmmaking to calibrate white balance and exposure. It reflects all colors equally, making it ideal for setting accurate tonal and color baselines.
Using a gray card helps cameras detect true neutral values, which leads to better color accuracy across scenes. It helps achieve consistent color and exposure across shots, especially in multi-camera setups or changing lighting conditions. It also helps match shots when using multiple cameras or changing lighting setups.
Place the gray card in the scene under your key light, then use your camera’s custom white balance function to sample it. You can also use it in post to auto-correct footage during color grading.
Place in scene lighting – Position the card under the same light as the subject for accuracy.
Use for calibration – Reference it when setting manual white balance or exposure levels in-camera.
Check consistently – Re-shoot gray card references when lighting changes during production.