There are many applications which use PPD files to know about the capabilities of printers, so that their printing dialogs can make available all options which the printer/its driver provide and also show additional information about the printer. In addition to applications as Star Office/OpenOffice.org, GIMP (for printers not supported by Gimp-Print), GPR, … PPD files can also be used on Windows, Mac, or LPD clients to get access to the printer's capabilities and options. foomatic-rip makes the full capabilities of PPDs available for all supported spoolers (CUPS, LPRng, LPD, GNUlpr, PPR, PDQ, CPS, spooler-less printiung).