323. Convenient Features Correcting Horizontal and Vertical Keystone Distortion [COR-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.Cornerstone1. Press and hold the 3D REFORM button for a minimum of 2 seconds to reset current adjustments.Current adjustments 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.Projected imageThe drawing shows the up-per right corner.4. Press the 3D REFORM button twice.The Cornerstone adjustment screen is displayed.5. Use the button to select one icon () which points in the direction you wish to move the projectedimage frame.6. Press the ENTER button.TIP: If you are adjusting [KEYSTONE], [CORNERSTONE] will not beavailable. If this happens, press and hold the 3D REFORM button for aminimum of 2 seconds to reset the [KEYSTONE] adjustments.The drawing shows the upper lefticon ( ) is selected.TIP: PA600X/PA500X: When [WIDE SCREEN] is selected from [SCREEN TYPE],lines that show “16:9” or “16:10” will be displayed. Click the outer corners.PA550W/P-PA500U: When [4:3 SCREEN] is selected from [SCREEN TYPE], linesthat show “4:3” will be displayed. Click the outer corners.