When shopping for a new monitor or printer buyers are bombarded with many different terms related to how the unit displays information on the screen or prints data to paper. Some users may think that terms such as "screen resolution," and "Dots per inch (DPI)" are the same thing when in fact they are completely different and used in completely different ways depending on the object being described. This article will define the differences between the two terms and demystify the context in which they are used.
A Definition of Screen Resolution
When looking at the specifications for a computer monitor a person will always find information about the maximum resolution of that monitor. In most cases the larger the monitor the higher the possible resolution, expressed in pixels wide by pixels high. 1024x768 is a common screen resolution for most 17 inch standard width monitors. Regardless of whether the numbers represent an LCD or a standard CRT monitor, most buyers will want to purchase a monitor that has the highest resolution possible. This number expresses the number of tiny pixels that are seen across and down the screen. Higher resolutions on huge monitors provide the user with lots of screen real estate to open documents and move objects around on the screen. Lower resolutions on larger monitors work very well for users with visual impairments.
A Definition of Dots Per Inch (DPI)
What resolution is to computer monitors, dots per inch is to printers. The overall DPI rating of a printer shows the buyer how tight together the printer is able to print the individual dots that make up an image. The higher the DPI the clearer the printed document will be. For most printed materials 600dpi is more than adequate although some laser printers can produce outputs much higher.
Comparing Screen Resolution to DPI
The difference between the resolution and dpi lies in that resolution ratings apply to pixels on a Video screen. All screens have a maximum DPI of 72, but their resolution is many times larger. For printers there is no such thing as resolution, only a rating having to do with DPI output.
