As a functional 18% grey reference square, the Calibrite ColorChecker Gray Balance is a full-size version of that found within the standard 24-patch ColorChecker. This is great for studio photographers and on-location shooting; allowing for a truly balanced mid tone grey value. You can confidently set up corrected studio lighting ratios between main and fill lights, use as the initial reference shot in a series, and can be used to adjust colours within common photo processing software packages. In short, the perceived colour of white actively changes based on ambient conditions. The ColorChecker Gray Balance gives you the power to adjust your camera's colour sensitivity to exactly match the ambient lighting conditions.