After securing a model release form, practice on sharp focus, stop the lens down to about U. S. 4, or to its equivalent, f/8. Now close the shutter and insert the plate holder in the opening at the side of the camera just in front of the ground-glass. Be sure that the projection or groove near the end of the holder fits snugly into the groove or projection on the hack of the camera. The plate holder should at perfectly flush, so that no light can enter between plate holder and camera to fog the plate.