Q. What is Dots per Inch?
DPI (Dots per Inch) is a measure for actual sharpness of onscreen image. This relies on both the resolution and size of the image. Practical experience shows that a smaller screen has a sharper image at same resolution than does a larger screen. This is because it will need more dots per inch to display similar number of pixels. A 15-inch monitor is 12-inches horizontally. A 10-inch monitor is 8 inches horizontally. To display a VGA image (640480) the 15-inch monitor will require 53DPI and the 10-inch monitor 80 DPI.