*** This is not to replace professional white balance *** ZehBounce systems. Com - is an easy way to make your images closer to the white balance without some known target in your images. This process can be done in Photoshop or Lightroom using a rebound Zeh as a carte blanche. Just pop in your Zeh your rebound setting for a shooting and then when you return to your computer to work on your images, call the white balance on your card with white and the WB eyedropper tool. This is not to balance the exposure white (gray card). Work in a pinch, if you do not have a passport or a color SpyderCube (TM) at hand. For more info on the rebound Zeh go to http://zehbounce.com also available from B & H photo.