Dpi Vs Ppi
PPI (pixels per inch) describes a digital image file's resolution at a given print size — how many of the file's actual pixels are packed into each inch. DPI (dots per inch) technically describes a printer's physical output resolution — how many ink dots it lays down per inch, usually a larger number than PPI, since most printers use multiple dots to represent the color and tonal range of a single image pixel.
In everyday photography conversation, the two terms are frequently used interchangeably, and most printing services and software surface 'DPI' even when they mean the image file's PPI at the printed size. The number that actually determines whether a print looks sharp is the file's PPI, not the printer's raw dot output — a printer capable of very high DPI doesn't reduce how many real image pixels your file needs for a given size.
Frequently Asked Questions
Should I set my file to 300 DPI in software before printing?
The setting that actually matters is your file's PPI at the intended print size — many editing programs use the label 'DPI' loosely for this same setting, so check that your pixel dimensions and print size combine to the density you actually need.
Does a higher-DPI printer let me use a lower-resolution image file?
No — printer DPI and image file PPI are separate specifications; a high-DPI printer still needs a file with enough real pixels to fill the intended print size at an adequate density to look sharp.