The Vidpro White Balance Dual Sided Disc for Digital Photography is an excellent tool for achieving perfect color balance and accurate exposure in your photos. You can use it under any lighting condition, both pre- and post-production. The Disc has two sides one is 18% grey with target "+" mark, the other side is white. This Disc can be used in film or digital photography, the 18% grey side can control exposure value, the white side can balance the color and the target "+" mark can provide accurate center photometric.It is the ideal accessory for the Pro Photographer for indoor and outdoor shots