Getting consistent colors from different Tektronix / Xerox printers

[Kirill Ponazdyr]

Hello,

We are looking for a solution which would allow us to get printouts
from our printers which are more or less consistent with the images we
see on the screen. For now we have no color calibration solution at
all. Our setup is following: 3 x Windows based Workstations with Dell
2001FP Monitors, Tek / Xerox 750 DX, 780 Plus and 850 DP Phaser
printers and a wide range of software, anything from normal office
applications through custom DB design tools to Photoshop &
Illustrator.

The unlucky thing is that although all printers come from the same
company, the printouts using the ICC profiles provided with them and
identical driver settings (TekColor is off in all cases) are very
different in colors. 750 produces rather light images, 780 rather dark
and 850 is closest to what we see on display but is still quite off.

Should not the ICC profiles supplied by manufacturer for those
professional grade printers (At least 750DX and 780P can be considered
professional units) offer at least more or less consistent results?
Also, if we disable ICC and rely on printer's own TekColor correction
mechanisms, prints improve a little (Especially with sRGB setting) but
are still far from being similar to each other and screen.

Is the dedicated color calibration solution the only way to go? And if
yes, which would suit our needs? So far I have found 3 which would fit
in our budget:

Monaco Optix XR + EzColor Bundle + good scanner
ColorVision SpectroPRO Suite
Gretag Eye-One Photo Suite

The problem is: I have no clue which one would fit best to our
environment, firstly most of them are targeting Inkjets, while our
printers are Laser / Solid Wax, secondly I have read very
contradictory opinions about ezColor, some say it is good, others
claim that all "Scanner-Based" tools are useless because of poor
scanners. ColorVision products seem to be old and Gretag Eye-One Photo
claims to profile RGB printers only.

Please help, I am lost

Best Regards

Kirill

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[Elmo P. Shagnasty]

We are looking for a solution which would allow us to get printouts
from our printers which are more or less consistent with the images we
see on the screen. For now we have no color calibration solution at
all.

calibration does not equal characterization. see below.

Should not the ICC profiles supplied by manufacturer for those
professional grade printers (At least 750DX and 780P can be considered
professional units) offer at least more or less consistent results?

ICC profiles are characterizations, thumbprints if you will, of a
calibrated device. ICC profiles do not provide consistency. Only
calibration can provide consistency. If you're not calibrating the
units, then they're inconsistent from day to day and week to week--and
no profile can make up for that kind of inconsistency.

Calibrate first and often. Only then, once the printer is calibrated,
can you make any judgment or take any actions on its color performance,
up to and including profiling its behavior.

Most importantly, the same is with your monitors. Do this: put the
exact same gray background on all three Windows workstations, put all
workstations side by side in the same room, and turn off the lights--and
look at the images on screen.

They won't match. Not by far.

So when you say "we want prints that are consistent with what we see on
the screen," I say, "which screen? The one on the left, in the middle,
or on the right? They're all different."

If you're looking to make the screen display the same thing that's
coming out of the printer, you have several things to do here.
Calibrate the monitors first. Then characterize them and make ICC
profiles, such that your color display engine knows how each individual
screen behaves. Do the same with your printers. Then tell your color
management engine on the computer to do all the right things (warning:
this subject takes books to explain).

IMPORTANT: when printing, manage your color exactly ONCE. I don't care
where, but do it exactly once. Not twice, not three times. Once. THIS
MEANS: if you have a color management engine running on your computer,
and if it is looking at the profile for your printer and is sending out
color managed data to your printer to take into account how your printer
behaves, that's fine--but turn OFF any such color management features in
your printer. Tell your printer just to print the incoming data
straight through, with no alteration other than running it through the
printer's calibration curve to compensate for the consistency thing.

 

[Kirill Ponazdyr]

ICC profiles are characterizations, thumbprints if you will, of a
calibrated device. ICC profiles do not provide consistency. Only
calibration can provide consistency. If you're not calibrating the
units, then they're inconsistent from day to day and week to week--and
no profile can make up for that kind of inconsistency.

Hmm, I am a little confused, but don't the most Calibration systems
output ICC as well?

So when you say "we want prints that are consistent with what we see on
the screen," I say, "which screen? The one on the left, in the middle,
or on the right? They're all different."

One particular at the moment But the aim is to have consistent
colors on all units. So Screen calibrator is a must!

IMPORTANT: when printing, manage your color exactly ONCE. I don't care
where, but do it exactly once. Not twice, not three times. Once.

I figured that out, and, at least under windows with Phasers there
seem to be 3 areas where color management can be performed:

1) Application itself such as Photoshop or Illustrator
2) ICM Management within the printer driver (ICM Handled by Host
system selection under Advanced -> ICM management of the printer
driver)
3) TekColor correction within the printer

Actually, when using Photoshop / Illustrator INTERNAL color management
functions with ICC profiles supplied by manufacturers we get quite
close results. But we would like to get good results with other apps
as well.

And another very basic question: What is the difference between RGB
and CMYC calibrations? Gretag Eye-One Photo claims it only calibrates
RGB Printers. Are Phasers RGB or CMYC printers?

Best Regards

Kirill
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[Elmo P. Shagnasty]

Hmm, I am a little confused, but don't the most Calibration systems
output ICC as well?

No. A calibration is simply a tone reproduction curve that's unique to
that printer at that moment in time. As that printer drifts, that TRC
becomes less and less useful. So you re-calibrate.

Every print job goes through that TRC as a final step before engine
marking commands are produced.

I figured that out, and, at least under windows with Phasers there
seem to be 3 areas where color management can be performed:

1) Application itself such as Photoshop or Illustrator
2) ICM Management within the printer driver (ICM Handled by Host
system selection under Advanced -> ICM management of the printer
driver)
3) TekColor correction within the printer

Correct. Pick one place to do it, and leave the others alone. Keep in
mind, your devices should be calibrated as well.

Actually, when using Photoshop / Illustrator INTERNAL color management
functions with ICC profiles supplied by manufacturers we get quite
close results. But we would like to get good results with other apps
as well.

Then you are 99% of the way there. You simply need to transfer that
process over to the printer.

If you're lucky, the printer's RIP will allow you to tell it to
acknowledge profiles that are included with the image.

And another very basic question: What is the difference between RGB
and CMYC calibrations? Gretag Eye-One Photo claims it only calibrates
RGB Printers. Are Phasers RGB or CMYC printers?

The Phasers are CMYK printers (only film recorders are RGB), but they
consume RGB. If Gretag says "we calibrate only RGB printers," it must
be because they're emitting RGB print streams from their profiling
software. Since the Phasers can take in those RGB streams and convert
them to CMYK, that's fine. But I don't really understand Gretag's
position here; I'd have to see the package.

I know for a fact that this package does a killer job:

http://www.efi.com/products/color_profiler.fhtml

 

[Richard Zhu]

I have written a Monitor calibration system with the sequel imaging probe,
and using the xyz space as the invariant space, and I use postscript mode to
pull out the xyz color directly out on HP and many hi end printer models,
sounds the results are way behind what we expect.
HP hi end ink give a better result thatn the Xerox wax, generally, I feel I
can get a 70% satisfaction on the color consistancy btw monitor and hi end
printers.

 

[Danny Rich]

Do the prints match each other if you create a standard RGB or CMYK
matrix of color patches in Photoshop? Have you set the rendering
intent of the output profile and input profile in Photoshop? Simply
loading the printer profile is not adequate to guarantee reproduction
to a monitor. How have you standardized the monitor? Is is balanced
for D65 or D50? Do you have an accurate profile of the monitor? What
is the ambient conditions? A hardcopy to softcopy match must also
control the ambient conditions, such as intensity and chromaticity of
the light source and surround.

Any of the systems you describe will be able to characterize your
printer and monitor. However, only you will be able to request the
correct combination of PCS parameters. This will require you to
thoroughly study the training details of each system.