Resolution and scanning quality Just like printers, the resolution of a scanner is given as dots per inch.
Interpolation is a simple method of enlarging pictures, but the results are dubious in quality.
Only the optical resolution is of interest. An optical resolution of 300 dpi is the lowest you can get, but in fact it is more than enough - even for printing on 1440 dpi printers. This is because printers use many dots together to create a particular colour, while the scanner simply sees every single dot as having it's own particular colour. Only buy a parallel port scanner if you truly can't afford anything else or if your scanning needs are very modest. Installation is simple, speed is reasonable and there are a lot of good USB scanners on the market now.