Resolution

Understanding Resolution

When you work with bitmap images like digital photographs, you work with pixels. A pixel (short for "picture element") is the smallest unit in a computer image or display. Every image on your computer is made up of a colored grid of pixels.

Your digital camera records pixels, your scanner converts physical images into pixels, your photo editing software manipulates pixels, your computer monitor displays pixels, and your printer paints pixels onto paper. In the digital world, "inches" don't exist, only pixels do.

The key to successfully editing, scanning, and printing images lies in understanding how pixels transform into inches and vice versa. Resolution is the interpreter between the physical world of inches and the digital world of pixels. When you scan an image, the scanner translates inches into pixels using resolution. When you print an image, the printer translates pixels into inches using resolution. So what's resolution? Unfortunately, the word is used in different ways in different contexts. "Camera resolution" usually means something slightly different from "image resolution", and "printer resolution" is something else yet again.


information taken from http://www.fotofinish.com/resources/centers/photo/resolution.htm