Dots-Per-Inch versus Pixels-Per-Inch

14/10/2008

Many people are inclined to use the terms DPI and PPI interchangeably, but that can be dangerously misleading. Web-to-print templates for print products should be using DPIs and web-to-print templates for banners and other on-screen templates should use PPI.

A software pixel is the basic building block of an image — it usually defines the smallest rectangular unit of detail an electronic document.

A hardware dot most often refers to the smallest specifically-colored block that a printer is capable of, in whatever density mode it is set to. One of the things that can be misleading is the difference between a printing dot (which is what the printer’s specs refer to when they mention “DPI“), and the ink dots that combine to form them.

“Dots” may also refer to the colored lights used in a display screen, either singly or in groups.”Dot Pitch” is the distance between one group and the next — or between, for example, one red light and the next red one …but not between a red light and a green one.

Especially when considering web-to-print, keeping track of DPI versus PPI is important. Generally, to smoothly produce an image with a given PPI, it should be printed at DPI setting at least two or three times greater.

Details of electronic document versus printed document

Details of electronic document versus printed document

See also: