Dan Margulis Applied Color Theory
How to Proof Pantone Colors
Date: Wed, 7 Apr 2004 14:46:43 -0400
From: John Toles
Subject: Protocol for Proofing Pantone Colors
Hi Folks,
I am wondering if those with far more experience at
this would care to comment?
I am trying to print accurate Pantone color swatches
with an Epson 9600. Here's my thoughts for a protocol.
Create a Photoshop file using Lab values for the
swatches. Print with "same as source" to avoid printer profiles.
Use "no color management" in the epson driver. Read the swatches
with spectrophotometer. Adjust Lab values in Photoshop file. Repeat .......
Any thoughts? Especially on how to minimize the
"repeat" step?
Cheers, John
http://www.dragonflyprinting.com/
http://www.dragonflygallery.ca/
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Date: Thu, 8 Apr 2004 07:00:40 +0100
From: Andrew Haley
Subject: Protocol for Proofing Pantone Colors
I'm confused. Is there any reason not to to use a
printer profile so that your initial values would be closer?
Andrew.
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Date: Thu, 8 Apr 2004 09:34:06 -0400
From: John Toles
Subject: Re: Protocol for Proofing Pantone Colors
Good question Andrew.
I figured that by removing all "black box"
variables I could better control the output. The printer driver isn't
linear, and the profile isn't linear. Together, that could make for some
unpredictable results. I could be proven wrong though :-)
What did you think about the rest of the methodology?
Cheers, John
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Date: Fri, 09 Apr 2004 00:12:28 -0000
From: Stephen Marsh
Subject: Re: Protocol for Proofing Pantone Colors
I am trying to print accurate Pantone color swatches
with an Epson
9600.
Accurate solid Pantone colours, right?
Create a Photoshop file using Lab values for the
swatches.
Working in which colour mode? RGB?? In which colour
space??? I presume that you are working direct in the profiled printer
space for this resolution/ink/stock - so that the RGB values are correct
for output with no alteration, as mentioned below.
Print with "same as source" to avoid printer
profiles.
The printer profile describes the profiled colour
output for you, otherwise you have to come up with the device values
yourself in the workflow that you are describing...not fun if you have to
figure out more than a handful of spot colours.
Use "no color management" in the epson
driver.
Read the swatches with spectrophotometer.
Adjust Lab values in Photoshop file.
Repeat .......
I think that most would approach the task in a similar
fashion to the following, this is not really my area and I would have
thought there would have been more input from other list members by now...
* Calibrate/Profile the printer at the
resolution/stock/ink that will be used for the spot colour proofing.
* Create your LAB value RGB or LAB or whatever mode
document. Print converting to the printer profile on the fly (relcol?) but
do not further colour manage these values upstream in the driver.
* Measure and visually evaluate the patches and see how
far from ideal they are, keeping in mind that you may not come close for
all colours, first time or even with tweaks.
I am not sure on the intended workflow, if you just
want to create your own spot colour 'chips' or if you then wish to use
these source values in your image files for more accurte proofing of solid
spot colours which do not interact with other inks and which are obviously
untinted, being solid.
It sounds like you will be manually editing the raster
files colour patches until they are correct?
Stephen Marsh.
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Date: Fri, 9 Apr 2004 10:13:42 -0600
From: Chris Murphy
Subject: Re: Protocol for Proofing Pantone Colors
On Apr 8, 2004, at 7:34 AM, Dragonfly Imaging &
Printing wrote:
The printer driver isn't linear, and the profile isn't
linear.
Together, that could make for some unpredictable
results.
I could be proven wrong though :-)
If you take a LAB document and try to print it, you get
color management no matter what because it's impossible to send LAB data to
an Epson printer driver. Photoshop will be forced to convert to your
working space (same as source should not even be an option, it should
default to your working space RGB), and if you then use No Color Adjustment
in the driver you will get absolutely totally whacked results and it will
take you years to edit the LAB file to get something sensible.
The problem with the methodology is that if you have
any white space between the swatches you're making, they will not print
white on the paper you are using unless it pretty much exactly matches up
with D50. The reason is that you need to use Absolute Colorimetric to print
out these sheet correctly or the matches won't be correct.
One of these days Adobe will get a clue and stop
attaching CMYK values to spot color libraries, and let us use LAB libraries
in InDesign. Then what you're wanting to do will be a lot easier.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolo
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Date: Fri, 9 Apr 2004 13:32:43 -0400
From: John Toles
Subject: Re: Protocol for Proofing Pantone Colors
Thanks for your advice Chris, Stephen and Andrew.
I stand corrected :-)
The pantone color swatches were given to me in Lab.
If I have this straight, my method should be to use Lab
document space in PS, my custom printer profile in print space, with
absolute colorimetric rendering, and no color management in the epson
driver.
I'm sure that will get me closer than where I am now.
I'll give it a try.
Cheers, John
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Date: Mon, 19 Apr 2004 14:03:56 -0400
From: John Toles
Subject: Re: Protocol for Proofing Pantone Colors
I just wanted to thank Chris, Stephen and Andrew again.
This job turned out to be a big headache. I never
thought that printing accurate pantone tolerance charts would be such a
pain!
It was compounded by their being close to the edge of
the epson dye and pigment color gamuts.
Photoshop did not convert from Lab to RGB in a
predictable fashion, when I chose Lab as 'source space' and my custom
printer profile with absolute rendering as the 'print space'.
In the end, I had to try every permutation of color
management I could think of, including: different profiles, printers, inks,
and papers.
The best method turned out to be: Convert Lab values to
the custom printer profile RGB space, and print 'same as source' with 'no
color management' in the epson driver.
John Toles
http://www.dragonflyprinting.com/
http://www.dragonflygallery.ca/
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Date: Mon, 19 Apr 2004 14:59:08 -0700
From: Paul D. DeRocco
Subject: RE: Protocol for Proofing Pantone Colors
From: Dragonfly Imaging & Printing
The best method turned out to be: Convert Lab values to
the custom
printer profile RGB space, and print 'same as source'
with 'no color
management' in the epson driver.
If that doesn't do the same thing, the only reason I
can think of is that the explicit conversion used a different rendering
intent.
Ciao,
Paul D. DeRocco
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Date: Tue, 20 Apr 2004 10:46:46 +0100
From: Andrew Haley
Subject: RE: Protocol for Proofing Pantone Colors
Paul D. DeRocco writes:
If that doesn't do the same thing, the only
reason I can think of is that
the explicit conversion used a different
rendering intent.
I agree. However, trying to do the Lab to RGB
conversions in Photoshop does seem to give very weird results, as I found
when I tried.
Some of this may be due to the difficulty of trying to
profile an "RGB" device that doesn't really use RGB!
Andrew.
Adobe Photoshop training classes are taught in the US by Sterling Ledet & Associates, Inc.