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PPA Printer-Support RPM Packages for Red Hat Linux and Compatible Distributions

The pnm2ppa project team

v0.30, July 9, 2002
Information and installation instructions to accompany pnm2ppa packages for Red Hat Linux available at (Updated for pnm2ppa-1.10 and Red Hat 6.2 or later.) See the "Troubleshooting" section at the end of this document for fixes to some reported problems

Overview of HP's PPA DeskJet Printers.

Most of Hewlett-Packard's DeskJet(tm) printers use the PCL3 command language, and are currently supported by Ghostscript drivers. However, a few legacy models, namely

feature "Host-based" printing, and use HP's proprietary PPA (Printer Performance Architecture) protocol, instead of PCL. The two models in each series are physically identical; they just came with different bundled Windows software. All PPA printers are now discontinued from HP's product lines, but may still be found as second-hand legacy items.

PPA printers rely on software running on the host CPU to carry out the low-level processing of printer output that would be done by hardware in a standard PCL printer. The relation of PPA printers to PCL printers is analogous to the relation between "Winmodems" and true modems. Presumably, the idea at the time was that this would allow cheaper hardware to be used, but the decline in hardware prices probably meant that the savings were not significant, and PPA printing seems to have been abandoned.

Unfortunately, HP only supplied Windows software drivers for PPA printers, and have indicated that it is unlikely that they will ever make the proprietary PPA specs public. This is apparently because of concerns that publication of the specs might reveal crucial details of HP's trade secrets about "color science" to competitors. (A secondary issue is that it is apparently possible to physically damage the printer by sending it bad sequences of PPA commands, which is not the case for PCL commands, and it seems that HP do not wish to take any responsibility for such damage by encouraging unofficial PPA programming.)

In the past, Linux users often inadvertently purchased PPA DeskJet models, mistaking them for PCL3 DeskJets, which have traditionally been well-supported by Linux drivers. Fortunately, a reverse engineering effort, started in 1998 by Tim Norman, and continued by the pnm2ppa project at, and has managed to produce drivers that provide basic printing functionality for these PPA printers under Linux and other Unices. While HP have recently begun to release their own Linux drivers for PCL3 DeskJets, they have not included drivers for their legacy PPA printers in this effort.

The pnm2ppa driver has been stable since v1.04, released October 2000, with no known reproducible bugs, except that image printing quality was not so good. This version has been distributed with Red Hat, and other Linux distributions. v1.10, released July 2002, contains a lot of changes that improve image quality, in particular by improved bidirectional printing, and always printing black on top of color.

A better improvement would be for someone to make a PPA backend to gimp-print, using pnm2ppa as a guide for how to send data to PPA printers. But, since PPA printers are now "legacy" hardware, and pnm2ppa appears to work fine for most printing tasks, it is unlikely that any new developers will be interested in doing this, and there is currently no further development anticipated. The project is currently in "low-maintenance mode".

The pnm2ppa driver for color printing with PPA printers.

Color printing with PPA printers is supported by the pnm2ppa driver which is the successor to the older black-and-white-only driver pbm2ppa-0.8.6 developed by Tim Norman.

pnm2ppa translates portable anymap (pnm) format images into a stream of PPA instructions which can be sent to the printer. In the driver name, "pnm" stands for the superset of three image formats: ppm (portable "pixmap" format for color images), pgm (portable "greymap" format for greyscale images), and pbm (portable "bitmap" format for black and white images).

Ghostscript has a number of "output devices" that produce pnm format output from postscript or pdf input. These come in plain (text) and raw (binary) variants. While pnm2ppa can now interpret both plain and raw pnm formats, there is no point in using the inefficient plain formats: always use the "raw" output devices, which are:

The last two output devices are switches that try to analyze the image, and select an appropriate format; however, they are not recommended for routine use, as they may inconsistently choose the format. The ghostscript packages supplied with all recent Red Hat distributions provides all these devices. To see the list of available ghostscript output devices, type the command line
gs --help
if the required ppmraw or pbmraw devices are not shown, you will have to upgrade your version of ghostscript.

The data must be streamed directly from ghostscript to pnm2ppa to the (local) printer without being stored in any intermediate file: one ppm-format (color) US Letter size page is represented by 3x5100x6600 Bytes (100MB) in binary format and four times this amount in text format.

An example of a command line for printing a postscript file using gs (ghostscript) and pnm2ppa is

cat | gs -q -sDEVICE=ppmraw -r600 -sPAPERSIZE=letter -dNOPAUSE \
 -sOutputFile=- - | pnm2ppa --eco -v 720  -i - -o - | lpr -l  
(all on a single line). In this example the paper size is explicitly given to gs as US Letter (8.5"x11") size (letter); pnm2ppa no longer needs to be told what the paper size is, and will read it from the gs output (and check that it is a permitted size for the printer type). The pnm2ppa option --eco specifies "EconoFast" mode, for a lower quality output which uses less ink, and prints faster, and -v 720 specifies the PPA printer as belonging to the DeskJet 720C series.

Obviously, it would be impractical to type such a command each time one wished to print something, and since RedHat 6.2, printfilter support for pnm2ppa is built into Red Hat's printer configuration scheme, so after configuration, the simple command

should successfully print a postscript file. However, in case you wish to check if something is misconfigured in the print filters, you can use a script like the above one to bypass them and check that the printer is working.

Available RPM packages. A RPM package for pnm2ppa is part of the Red Hat Linux distribution starting with Red Hat 6.2. You will also find a RPM package for the latest release of pnm2ppa at

The latest version at the time of writing is pnm2ppa-1.10-1rh7x.i386.rpm, and is built on Red Hat 7.3, or pnm2ppa-1.10-1rh62.i386.rpm, built on Red Hat 6.2. If you are running a different release of Red Hat (or a different Linux distribution) you may need to download and rebuild the source RPM pnm2ppa-1.10-1.src.rpm instead:

rpm --rebuild pnm2ppa-1.10-1.src.rpm
(You must be root to do this, and have the necessary compilers installed; on Red Hat, the rebuilt binary RPM will be created in the directory /usr/src/redhat/RPMS/i386/.)

Red Hat 6.2 and later also includes support for configuring your printer to use pnm2ppa. (Information necessary for configuring pnm2ppa on older Red Hat releases has been removed from this document; for this, see the documentation that came with pnm2ppa-1.04, or update your RedHat distribution.) Note: If you are still using Red Hat 6.2, you may wish to update the print filter support for pnm2ppa that comes with it. The pnm2ppa-1.10-1rh62* RPM package supplies the necessary files that you can use. After installing this RPM, see /usr/lib/rhs/rhs-printfilters/README.ppa for details.

Installing the pnm2ppa RPM package and setting up the PPA printer.

To install the RPM package, you must log in as the system administrator, root.

Now begin the installation. First install the pnm2ppa RPM:

rpm -Uvh pnm2ppa-1.10-1*.i386.rpm
The pnm2ppa executable gets installed in /usr/bin/.

The Linux kernel will be able to autodetect IEEE-1284 devices like PPA printers, provided they are attached to the parallel port with a bidirectional IEEE-1284 cable. (If your printer works under Windows, you have the correct cable.) A script detect_ppa is provided by the pnm2ppa RPM: just type

to confirm that your Printer is found. A typical message from the printer, which will be displayed if autodetection is successful, is:
DESCRIPTION:Hewlett-Packard DeskJet 820C;
A list of PPA printers found, and the parallel ports to which they are attached, will also be shown.

At this point it is useful to test that your printer is working, by printing a test page using the supplied script test_ppa which the RPM has installed. You will need to know your printer model (710, 712, 720, 722, 820, 1000), your paper size (letter, legal, a4) and the printer port the printer is attached to. If it is attached to the primary parallel port, this is (usually) /dev/lp0. Type

and give the details about printer model. papersize, and port number when prompted. You will then be asked whether to print a test page, an offset calibration page, or an alignment calibration page, etc.

Configuring the print filters.

Note: Red Hat 7.3 now features either CUPS or LPRng printer management. The configuration tools should be able to configure pnm2ppa, using the information about it taken from the Linux Printer Database. Apart from the addition of a new --dpi300 option to accept 300dpi input (useful for printing PNM output from 300dpi scanners), there have been no changes in the pnm2ppa command line since the pnm2ppa-1.0 release, so the configuration scripts are stable. (They can only use the default 600dpi input mode.)

Since Red Hat 7.1, there is a graphical printer configuration utility printconf-gui. In Red Hat 6.2 and 7.0, the older configuration utility called printtool is used. In either case, start the "Red Hat Linux Print System Manager" (as root) to configure the printer, either by clicking on the printer icon in Red Hat's "control-panel", or just typing

which also starts printconf-gui in the newer Red Hat releases.

Configuring the print filters with the Red Hat 6.2/7.0 printtool

(Skip this section unless you are still using Red Hat 6.2 or 7.0)

The following description is for the older printtool that is used by Red Hat 6.2/7.0. The printer configuration utility printconf-gui for Red Hat 7.1 and later is a little different, as it is based on the foomatic printer configuration database which contains entries for pnm2ppa (but not the older pbm2ppa). You should be able to easily figure out what to do: it can configure all pnm2ppa command-line options in the Driver Options screen.

In the Red Hat 6.2/7.0 Print System Manager window, click on Add, then in the "Add a Printer Entry", select Local Printer, and click Ok. Hopefully, the port on which the printer is attached will be listed as "Detected" (if not, fix the problem before continuing, perhaps by adding the line "alias parport_lowlevel parport_pc" to /etc/conf.modules). You will now have to "edit the local printer entry" for the PPA printer. Click on Select to chose the "Input filter". The Configure Filter screen will open. Among the many printer entries in the list "Printer Type", you should find three entries

Select the appropriate entry for your printer model. You will then be presented with various options: When you have made your choices, click on Ok to save your selections and close the "Configure Filter" screen, and then click on OK to close the "Edit Local Printer Entry" screen.

You are now back in the "Red Hat Print System Manager" screen; highlight the printer you just configured, and, in the Tests menu, choose Print Postscript test page to print a test page using the Red Hat print filters. If this printed correctly, your print system is set up to use the PPA printer, just like any of the other printers that the Red Hat print filters support.

Configuring pnm2ppa.conf and calibrating the printer.

A number of printer parameters are set to reasonable default values for each of the printer models, but you may wish to "fine tune" or calibrate your printer. The default values can be overridden by entries in the configuration files, which by default are /etc/pnm2ppa.conf and /etc/pbm2ppa.conf. At 600dpi, one pixel is 1/600 inch.

The user-adjustable parameters are:

Use test_ppa to print various test pages or calibration patterns to adjust the offsets.

If you wish to specify these parameters using the command-line options described above, in Red Hat 6.2/7.0 some of them can be entered in the "extra GS options" box using the Print System Manager (printtool), as described above. In Red Hat 7.1 and later, all command-line options can be set using the new printconf-gui utility.

Utility programs for the printer.

HP's Windows software provides a utility program that sends PPA commands to tell the printer to perform tasks like cleaning the printheads, etc.

On Red Hat Linux, You can use test_ppa (which acts as a command-line front-end for calibrate_ppa) to print head-cleaning patterns.

There is a graphical (gtk-based) tool written by Javier Sedano for creating a pnm2ppa.conf file and acting as a front end to calibrate_ppa. This is called ppaSet, and a beta version of it can be found in the same place as the pnm2ppa-1.10 distribution at

There was also at one time a proposal to add support for PPA printers to the PUP (Printer Utility Program) utility, which is also a project at However, as of the time of writing, no PUP support for PPA printers is available.


The first thing to do is to look at the messages from pnm2ppa in the system log to see what is happening, whether pnm2ppa actually received any input, and if it was valid. (You may need to enable system log messages in /etc/pnm2ppa.conf, see above.) Maybe ghostscript failed to convert your postscript file into PNM format: in that case the system log reports "Fatal Error! Input image (pnm2ppa) is not a PNM image". (note: when this occured, older versions of pnm2ppa reported "Input image is not a supported PNM format" which may have been confusing). This is because the input received by pnm2ppa was not a valid PNM image, but instead ghostscript failed to produce any PNM output at all, and its only output was probably just an error message. This is not a pnm2ppa problem!

Here are suggestions for dealing with other problems that you may encounter.

Contacting the pnm2ppa project.

Send comments or corrections (about this document or the RPMS) to:

There are three mailing lists, (announcements), (users helping users) and (developers). You can subscribe to them, or browse their archives, at (The older pnm2ppa mailing lists died with the ListBot service)

To contact the developers, subscribe to ppa.devel and post a message.

There are Public Forums for posting questions and comments at (but whether you get any help from these, depends on whether anyone is reading them (unlikely!)).

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