Setup and Configuration IV
Unfortunately, 'PrinterDrake' does not offer to choose a default printer
(i.e. a printer which would respond to lpr [file name]) and the
"Default Printer" command in the right-click-on-printer-menu of 'Kups' only
works for local printers (because it stores the setting in
'/etc/cups/printers.conf', where only local printer queues are listed).
To set up a system-wide default printer, login as 'root' and type:
lpoptions -d [name of the desired default printer]
This stores the information about the default printer in
'/etc/cups/lpoptions'. Former LPD users might use lpoptions -d lp
to make "lp" the default printer because "lp" was the hard-coded default
printer name of LPD. Alternatively you can also run xpp as
'root', choose the desired default printer and then click on the "Options"
button and then on "This printer as default" in the options dialog. Close the
dialog with "OK" and the main window with "Cancel" (you do not want to print
now).
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Color printers often print colors not exactly as they appear on the screen.
To fix this, one does a color calibration. Unfortunately, the possibilities
for doing this calibration differ a lot from printer to printer (or from
driver to driver). Color laser printers (like the Tektronix Phasers) have an
integrated color calibration system which is operated by the buttons on the
printer or by its web interface (Ethernet-connected models). These systems
print a special test page for comparison with the screen output of pure
yellow, magenta, and cyan and you have to enter the numbers of the blocks
looking most similar to the screen output in the printer interface.
Color adjustment for ink jets is often done by special Windows programs and
so it cannot be done under Linux. It even does not help to boot into Windows
for the calibration and to go back afterward, because the correction values
are stored in the Windows driver's configuration files and not in a
non-volatile memory of the printer.
So color calibration on inkjets under Linux must be supported by the Linux
drivers. At least these drivers support some form of calibration: the
GIMP-Print drivers, the GhostScript drivers for many HP PCL ink-jets, the
driver for the HP PPA win-printers, the drivers delivered with CUPS, and the
drivers of the commercial product ESP Print Pro (demo on the commercial CDs of
the Power Pack). So for most Epson, Canon, and HP DeskJet printers there is at
least some form of color adjustment.
The best solution is provided by all native CUPS drivers.
Native CUPS drivers are drivers which do not use Ghost Script, but
the filters delivered with CUPS (for PostScript there is a modified Ghost
Script in the CUPS package). For these drivers there is a program which leads
you step-by-step through the calibration process.
To use it, you must first configure your printer to use such a driver.
Search for a driver entry starting with "CUPS + GIMP-print v4.0", "CUPS v1.1",
or with "ESP Print Pro" in 'PrinterDrake' or the web interface of CUPS. In
'Kups' you have to search for model entries which begin with the printer
manufacturer's name, as in "HP DeskJet 840C" (and not "DeskJet 840C"). Click
on the "Show options" button of the appropriate entry and you will see the
"CUPS + GIMP-print v4.0", "CUPS v1.1", or "ESP Print Pro" entries above the
options tree.
To calibrate, choose "Configuration"/"Printing"/"Calibrate color printer"
in the desktop menu (command line: calibrate-gimpprint) and
follow the instructions displayed.
Enter the paper type and resolution exactly as on the command line
(lpr command, see the output of the lphelp command).
You will see color samples which are numbered from "0" to "9" and after "9"
from "A" to "F" (from the right to the left). Just look for the most suitable
sample and enter its number (or the numbers of two samples if the best result
lies between two samples).
Use a graphics program like 'The Gimp' or 'KIllustrator' to get pure red,
green, blue and black on the screen (densities 100 %, 50 %, and 25). Then you
can compare the samples to the screen display.
When you're finished, you can save the calibration as a default option either
system-wide in '/etc/cups/lpoptions' (when you did the calibration as 'root')
or in your personal '~/.lpoptions' file, when you did the calibration from
your user account. Alternatively, you can put the line starting with
"*cupsColorProfile", displayed and printed by the calibration
program, into the PPD file of the printer ('/etc/cups/ppd/[printer
name].ppd').
Note: Calibration is ignored by the "Test Printer" function in the
right-click-on-printer-icon menu of 'Kups'.
If your printer is not supported by any native CUPS drivers, you should
check with 'Kups' or with lphelp whether there are options to
adjust the levels of the three basic colors yellow, magenta, and cyan (note
that the web interface of CUPS does not support adjustment options). Print the
CUPS test page (lpr -P [printer name]
/usr/share/cups/data/testprint.ps or right-click on the printer icon
and "Test Printer" in 'kups') and compare the page with the screen display
("Configuration"/"Printing"/"Display printer test page" in the desktop menus).
Adjust the colors by changing the appropriate color settings. In 'Kups', click
with the right mouse button on the printer icon and choose "Configure Printer"
in the pop-up menu. For the command line see the output of man
lpoptions and lphelp.
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