To determine the optimal scanning resolution, use the following rule of thumb formula:

Dots Per Inch (dpi) = 2 x lines per inch x percent of resizing of the photo. The result of this equation is the correct scan-in resolution. It is necessary to know the final size of what you are scanning before you begin scanning. Example: A 4 x 5 photo that is going to be printed at 150 line screen for a new size of 8 x 10 requires enlarging the photo by 200 percent. The formula for this particular scan would be: 2 x 150 x 2 = 600 dpi, which indicates you should scan the photo at 600 dpi.

Resolution is a measure of graphics that is used to describe what a printer can print, a scanner can scan and a monitor can display. In printers and scanners, resolution is measured in dots per inch (dpi) – the number of pixels a device can fit onto an inch of space.

A Monitor's Resolution refers to the number of pixels in the whole image, because the number of dots per inch varies depending on the screen’s dimensions. For example, a resolution of 1,280 x 1,024 means that 1,024 lines are drawn from the top to the bottom of the screen, and each line is made up of 1,280 separate pixels – and, in turn, each dot may have any number of combinations of red, green and blue intensities.

Common Resolutions in the PC world include 640 x 480 (also called VGA resolution; appropriate for a 14-inch monitor), 800 x 600 (appropriate for a 15-inch monitor), 1,024 x 768 (appropriate for a 17-inch monitor) and 1,280 x 1,024.

Web site graphics are designed and built at a screen resolution of 72 or 72 dpi. This is not a recommended resolution for printing. Images from Web sites will appear “chunky” or “jagged” due to the lack of information if printed at 300 dpi.

Printer Resolution is measured in dots per inch (dpi) PrintComm needs photographs and artwork to be a minimum resolution.