The following chart is for the AppleVision 1710AV Display. It shows the front of screen DPI when the display image is set up with a 300mm by 225mm raster image (Apple specifications). This size image leaves about 1/2 to 3/4-inch black border between the raster edge and the front bezel plastics. Most resolutions have the same horzontal and vertical DPI except the 1280x1024 resolution.
Resolution Dots per inch
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640x480 54 (H & V)
800x600 68 (H & V)
832x624 70 (H & V)
1024x768 87 (H & V)
1152x870 98 (H & V)
1280x960 108 (H & V)
1280x1024 108 horizontal, 116 vertical
1600x1200 135 (H & V)