Whats the difference between pixels and dots per inch? Is a dot a pixel?
A pixel is a minute circular point of light about 10 or 12 thousandths of an inch in diameter (sometimes stated as 10 or 12 ‘mils’) created on a monitor screen. A dot is a sample taken by a scanner for representation in a raster image. A 300 dots per inch (dpi) scan takes snapshots of dots which are about 3 mils across (3,33333….mils to be exact). To represent a 300 dpi scan on screen at a 1:1 scale your computer typically has to consolidate groups of 16 dots (each 3.33… mils diameter) into a single pixel (10 – 12 mils diameter) This means that the raster image you see on screen is only an approximation of the underlying digital ‘dpi’ information from your scan. And your scan itself is an approximation. Sometimes the screen appearance can be disconcerting.
