gs-pcl3.ref

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and
<userinput>-sMedium</userinput>.
You should also check whether there is an entry in the
<filename>reports.txt</filename> file
in the <command>pcl3</command> distribution
listing working option combinations for your printer.
</para>

<!--========================================================================-->

<refsect2><title>Standard Options</title>

<para>
When calling <command>gs</command> with the <command>pcl3</command> driver 
you can specify any option defined for ghostscript's
<command>prn</command>
(printer) device although some have particular meanings or restrictions.
This includes all device-independent options described in
<citerefentry>
  <refentrytitle>gs</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>.
You should also look into ghostscript's extended documentation
(file <ulink url="Use.htm"><filename>Use.htm</filename></ulink> and the section
<ulink url="Language.htm#Device_parameters"><citetitle>Device
parameters</citetitle></ulink>
<!-- VERIFIED: Link checked for gs 5.50 and gs 6.50. -->
in <filename>Language.htm</filename>).

</para>

<variablelist>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-sDEVICE=pcl3</userinput></term>
<listitem><para>This specification selects the <command>pcl3</command>
driver,
but this is not the only way to select it with this option.
See the description of the <option>Subdevice</option> option below for other
possibilities.
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-dDuplex<optional>=<replaceable>boolean</replaceable></optional
></userinput> or <userinput>-dDuplex=null</userinput></term>
<listitem><para>
This parameter requests duplex printing and can be set to
<userinput>true</userinput> only for <userinput>unspec</userinput> and
<userinput>unspecold</userinput>,
and when the
<option>DuplexCapability</option> value is not <userinput>none</userinput>.
The default is <userinput>null</userinput>
which for this driver means that the printer's default setting will be used.
</para>

<para>
If your printer does not support duplex printing you can achieve the same
effect manually by printing the odd and even pages separately
(use a command like <citerefentry>
  <refentrytitle>psselect</refentrytitle>
  <manvolnum>1</manvolnum>
</citerefentry> from the psutils package for extracting these parts)
and reinserting the paper in between.
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-r <replaceable>resolution</replaceable></userinput></term>
<listitem><para>This option specifies the resolution in
pixels per inch (ppi; sometimes also called dots per inch, dpi).
<!--  Strictly speaking, the concept here is addressability, not resolution,
      because the option sets the number of pixels sent to the printer, not
      what it really prints. For the same reason, using "dpi" would actually be
      wrong. -->
The driver checks whether the subdevice selected accepts the given
resolution unless the subdevice is <userinput>unspecold</userinput> or
<userinput>unspec</userinput>.
Resolutions supported by at least some of the other subdevices
for some of the colour models are 75, 100, 150, 300, 600&times;300 and 600 ppi.
Consult the PPD files in the <command>pcl3</command> distribution if you want
to know the details.
The default resolution for <command>pcl3</command> is 300 ppi.
</para>

<para>
At least the highest possible value should be listed in your printer's manual,
but some care is necessary in the interpretation:
the value given to <command>pcl3</command> must be a resolution supported by
the printer's hardware for all the colorants in the process colour model
simultaneously and when operating in raster graphics mode.
You should also keep in mind that if your printer has two cartridges
they might support different sets of resolutions,
i.e., which resolution you can choose might depend on the colour model.
It is also possible that the print quality has to be considered as well.
If you are in doubt and have access to a manufacturer-endorsed driver for your
printer,
use <command>pcl3opts</command> to find out about the settings used by that
driver.
</para>

<para>
At least some of the series-500 DeskJets claim to
permit a resolution of 600 &times; 300 ppi.
However,
although these models have a 600 dpi addressable horizontal resolution grid
they do not permit neighbouring pixels to be activated
(and the dots printed still have a diameter of about 1/300 in).
The raster data generated by
<command>gs</command>
does not obey this restriction.
In addition, it is possible that the higher resolution is anyway only supported
for the printer's builtin fonts and not for general raster data.
</para>

<para>
Concerning the DeskJet 870C,
my impression is that although some HP documents and drivers use expressions
like "600x300 dpi C-REt color" for this printer,
the model does not really support a resolution of 600 &times; 300 ppi.
First, it does not accept <command>pcl3</command>'s output with this resolution,
and second,
if one inspects the best output of HP's Windows driver for this printer
with <command>pcl3opts</command>,
one finds that the file uses a "mixed resolution",
i.e., 600 ppi for black and 300 ppi for CMY.
This is not supported by <command>pcl3</command>.
</para>
</listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

</variablelist>
</refsect2>

<!--========================================================================-->

<refsect2><title><command>Pcl3</command>-Specific Options</title>

<variablelist>

<varlistentry>
<term><userinput>-dBlackLevels=<replaceable>levels</replaceable></userinput
> and <userinput>-dCMYLevels=<replaceable>levels</replaceable></userinput
></term>
<listitem><para>
These options set the number of intensity levels per pixel and colorant
to use when printing with black or CMY inks, respectively,
and must be consistent with the colour model.
They permit access to the printer's
Colour Resolution Enhancement technology (C-REt) feature.
The defaults are 0 or 2, depending on the colour model chosen.
Other values are only accepted for the subdevices
<userinput>hpdj8<replaceable>nn</replaceable>c</userinput>,
<userinput>hpdj1120c</userinput>
and <userinput>unspec</userinput>,
and when not using the colour model <userinput>RGB</userinput>.
</para>

<para>
The subdevice <userinput>unspec</userinput>
accepts any non-negative number of levels except 1 up to 256.
The subdevices <userinput>hpdj8<replaceable>nn</replaceable>c</userinput>
and <userinput>hpdj1120c</userinput> accept the
<replaceable>levels</replaceable> 0, 2, 3 and 4
with the following restrictions if any of the levels is larger than 2
(these restrictions have been determined experimentally with a
DeskJet 850C and are not based on HP documentation):
</para>
<itemizedlist>
<listitem><para>
You can't use this feature with draft quality.
</para></listitem>
<listitem><para>
You can't use a colour model of <userinput>CMY</userinput>.
</para></listitem>
<listitem><para>
You must use a resolution of 300 ppi.
</para></listitem>
<listitem><para>
You must use 4 levels for black.
</para></listitem></itemizedlist>
<para>
When using the subdevice <userinput>unspec</userinput>
you should expect the printer to similarly limit the possibilities.
In particular you must expect the permitted number of levels to depend on
colour model, resolution and print quality.
So far I have not heard of a PCL-3+ printer supporting more than
four intensity levels per colorant.
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-sColorModel=<replaceable>model</replaceable></userinput
> or <userinput>-sColourModel=<replaceable>model</replaceable></userinput></term>
<listitem><para>
This selects the colour model to be used by the driver:
<userinput>Gray</userinput>,
<userinput>RGB</userinput>,
<userinput>CMY</userinput>, <userinput>CMY+K</userinput> or
<userinput>CMYK</userinput>.
The default is <userinput>Gray</userinput>.
Which colour models are accepted depends on the subdevice, see
<link linkend="ColourModels"><citetitle>Colour Models</citetitle></link>
in the section <citetitle>DESCRIPTION</citetitle> above.
</para>

<para>
A value of <userinput>CMY</userinput> for this option also sets
<userinput>BlackLevels</userinput> to zero,
<!-- Note that "BlackLevels" in the previous line is deliberately not marked up
     as an option. -->
and if
<userinput>CMYLevels</userinput>
is zero when you demand any of <userinput>CMY</userinput>,
<userinput>CMY+K</userinput> or <userinput>CMYK</userinput>,
it is set to two.
For <userinput>RGB</userinput>, effectively the same happens as for
<userinput>CMY</userinput>.
For all other situations you must ensure yourself that colour model and
intensity levels are consistent or <command>pcl3</command> will complain.
This rule implies that you can ignore the level options unless you
want to use a non-default number of levels.
</para>

<para>
The PostScript page device dictionary entry
<literal>ProcessColorModel</literal> will not be correct for a colour model of
<userinput>CMY</userinput> or <userinput>CMY+K</userinput>.
(Ghostscript returns the native colour space in this parameter,
not the process colour model.)
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-dCompressionMethod=<replaceable>method</replaceable></userinput></term>
<listitem><para>
PCL interpreters understand several compression methods for raster graphics
data in order to speed up host-printer communication.
The possible choices are:

<informaltable><tgroup cols="2">
<tbody>
<row><entry><userinput>0</userinput></entry>
  <entry>Unencoded, non-compressed</entry></row>
<row><entry><userinput>1</userinput></entry>
  <entry>Runlength encoding</entry></row>
<row><entry><userinput>2</userinput></entry>
  <entry>Tagged Image File Format (TIFF) revision 4.0 "Packbits" encoding </entry></row>
<row><entry><userinput>3</userinput></entry>
  <entry>Delta Row Compression</entry></row>
<row><entry><userinput>9</userinput></entry>
  <entry>Compressed Replacement Delta Row Encoding</entry></row>
</tbody></tgroup></informaltable>

The default method is 9 except for the subdevices
<userinput>hpdj</userinput>,
<userinput>hpdjplus</userinput>, and
<userinput>hpdj500</userinput> where it is 3
(these printers do not support method&nbsp;9),
and for the subdevices <userinput>unspec</userinput> and
<userinput>unspecold</userinput> where it is 2
(this seems to give the best combination of portability and compression).
Requesting method 3 actually leads to a combination of methods 2 and&nbsp;3.
The driver may temporarily choose method 0 if a compressed data sequence would
be longer than its uncompressed version.
</para>

<para>
Compression rates can vary drastically, depending on the structure of the input.
However, although the absolute values change, the relative order of efficiency
between the methods is usually the order of increasing
<replaceable>method</replaceable>.
In short: use method 9 if it is supported.
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-dConfigureEveryPage<optional>=<replaceable>boolean</replaceable></optional></userinput></term>
<listitem><para>
This parameter, if set to true, will force the printer to be reconfigured for
every page.
The option is superfluous for printers which are truly PCL-3-conforming.
</para>

<para>
Use this parameter if you discover that you can print single-page documents
without problems but that the printer does not accept multi-page files.
At present, the only printer I know of for which such a reconfiguration is
needed is the Xerox DocuPrint&nbsp;M750.
</para></listitem>
</varlistentry>

<!-- ______________________________________________________________________ -->

<varlistentry>
<term><userinput>-dCUPSAccounting<optional>=<replaceable>boolean</replaceable></optional></userinput></term>
<listitem><para>
You will usually specify this parameter when using <command>pcl3</command> as
the final component in a CUPS (Common UNIX Printing System) driver.
<!-- CUPS "driver": set of filters. -->
It will lead to appropriate page accounting messages on standard error.
The default for this parameter is <userinput>false</userinput>.
</para>

<para>
If you have set this parameter to <userinput>true</userinput> you can't set
it back to <userinput>false</userinput>.
The driver will generate a warning if this is attempted.
</para>

<para>
When using <command>pcl3</command> within CUPS you will normally set both,
<option>CUPSAccounting</option> and <option>CUPSMessages</option>.
There exist, however, CUPS configurations where page accounting messages should
be generated by a command further down the print pipeline than
<command>pcl3</command>
(e.g., by a CUPS backend capable of processing PJL Page Status messages