For at producere rastede bitmaps fra & PostScript; inddata bruges filter - begrebet af & ghostscript;. Der er mange forskellige filtre i & ghostscript;, nogle af dem specialiseret til en bestemt model af en printer. & ghostscript; - filter til bestemte enheder er ofte blevet udviklet uden samtykke eller støtte fra vedkommende der fremstillede enheden. Uden adgang til specifikationerne og dokumentation, var det en pinefuld proces at 'reverse engineer' protokoller og dataformater.
To produce rasterized bitmaps from & PostScript; input, the concept of filters is used by & ghostscript;. There are many different filters in & ghostscript;, some of them specialized for a certain model of printer. & ghostscript; filter devices have often been developed without the consent or support of the manufacturer concerned. Without access to the specifications and documentation, it was a very painstaking process to reverse engineer protocols and data formats.