PostScript Printer Description (PPD) Specification
While PostScript in essence is a PDL to represent the page layout in a device-independent way, real-world
print jobs are always ending up being output on hardware with device-specific features. To take care of all
the differences in hardware and to allow for innovations, Adobe has specified a syntax and file format for
PostScript Printer Description (PPD) files. Every PostScript printer ships with one of these files.
PPDs contain all the information about general and special features of the
given printer model: Which different resolutions can it handle? Does
it have a duplexing unit? How many paper trays are there? What media
types and sizes does it take? For each item, it also names the special
command string to be sent to the printer (mostly inside the PostScript
file) in order to enable it.
Information from these PPDs is meant to be taken into account by the
printer drivers. Therefore, installed as part of the Windows
PostScript driver for a given printer is the printer's PPD. Where it
makes sense, the PPD features are presented in the drivers' UI dialogs
to display to the user a choice of print options. In the end, the
user selections are somehow written (in the form of special
PostScript, PJL, JCL, or vendor-dependent commands) into the PostScript
file created by the driver.