A PRN file is a special type of file which contains instructions for
a printer, it tells the printer what to print on the page and where
as well as which paper tray to use, what the paper size is and a
number of other controls.
PRN files are usually created automatically by a printer driver, in
fact this is the primary purpose of the printer driver, to translate
the generic output from an application such as Word or Notepad into
something the printer can understand and interpret.
Normally this whole process of creating the PRN file is transparent,
you print a document in your favourite application and the paper
starts feeding through the printer. There can however be some uses
for intercepting and capturing a PRN file before it gets to the
printer. Having the PRN file allows you to reprint the document
without running or even having the original application that created
the file, for instance if you run a print shop with a wide format
plotter and your customers use AutoCAD to produce plots you can have
them send a raw PRN file and output using that without needing
There are two main formats of PRN file and a huge number of bespoke
formats for mainly inkjet printers. The two formats we will look at
are PostScript and PCL.
PostScript is described as a page description language and was
developed by Adobe in 1984 and continues to be used on high volume
printers, typesetting equipment and optionally on many mid size
devices. It also had a brief foray into use as a display language on
the Next systems. PostScript is a fully-fledged programming language
and offers and extraordinary level of flexibility in the printing
process. PostScript files can be easily converted to PDF files using
Adobe Acrobat or even viewed using tools like GhostScript.
Hewlett Packard created PCL (Printer Command Language) for its first
laser printer the original HP LaserJet again in 1984. PCL is a much
simpler format than PostScript and in its early versions offered
much better performance than PostScript but less functionality. Over
time the format has developed substantially and PCL offers most of
the functionality of PostScript, certainly enough for the typical
office printing requirements. PCL is supported on virtually all
laser printers with the exception of some very low volume devices.
The current version of PCL is PCL6 although PCL5e is still used
extensively. PCL files can be viewed using 3rd party software.
Finally there are a number of other PRN file formats most of them
specific to certain types of printers such as low volume ink jet
devices or old style dot matrix printers.
Capturing a PRN file is quite straight forward, most applications
offer a "Print to file" option when you open the normal print
dialog, this image shows the print dialog from word for instance:
If your application doesn't support the "Print to file" option then
you could create a printer which uses the FILE: port or even use
some software such as Print Distributor which offers a very flexible
solution for capturing print files.
To print a captured print file you can send it on to a print queue
at the command prompt, just use the command:
Copy filename.prn \\computername\printersharename
This assumes you have shared your printer.