43 Correcting Horizontal and Vertical Keystone Distortion (Cor-nerstone)Use the 3D Reform feature to correct keystone (trapezoidal) distortion to make the top or bottom and the left or rightside of the screen longer or shorter so that the projected image is rectangular.4. Convenient FeaturesScreenProjected imageCornerstone1. Press and hold the 3D REFORM button for a minimum of 2 seconds to reset current adjustments.Current adjusments for “Keystone” or “Cornerstone” will be cleared.2. Project an image so that the screen is smaller than the area of the raster.3. Pick up any one of the corners and align the corner of the image with a corner of the screen.The drawing shows theupper right corner.4. Press the 3D REFORM button on the remote control twice.The Cornerstone adjustment screen is displayed.Screen5. Use the SELECT button to select one icon which points in the direction you wish to move theprojected image frame.6. Press the ENTER button.7. Use the SELECT button to move the projected image frame as shown on the example.