Quick answer

DPI means dots per inch. In printing, it commonly describes how many physical ink or toner dots a printer can place across one inch; it is different from an image's pixels per inch.

Original example

Pixels and printer dots are not one-to-one

A printer may use several colored ink dots to reproduce the color of one image pixel. A 300 PPI image therefore does not require a printer setting of exactly 300 DPI.

DPI versus PPI

PPI connects image pixels to physical inches. DPI describes printer marking resolution or settings. Printer software translates image pixels into device-specific dot patterns.

The useful settings depend on the printer, paper, inks, image, and viewing distance; one number cannot guarantee quality.

Common misunderstandings

  • DPI and PPI should not be used as interchangeable labels.
  • A larger advertised DPI number does not by itself describe the quality of an input image.

Related answers

Sources

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