Re: Lost in ICC Land
Re: Lost in ICC Land
- Subject: Re: Lost in ICC Land
- From: Darrin Southern <email@hidden>
- Date: Mon, 23 Apr 2001 16:16:04 +1000
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Darrin Southern <email@hidden> wrote:
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> With the latest range of 6 color (CYMKcm) inkjets, their densities are much,
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> much higher than the above mentioned printing or analog proofing methods.
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Henrik Holmegaard <email@hidden> wrote:
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> Also the press inks and your inkjets inks have different colors. Even
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> the blacks are a different color.
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So far we're saying the same thing, no?
We are agreeing.
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Also inkjet inks penetrate the paper and don't sit on top of the
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paper the way fatty offset inks do. So we want to control densities
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in very different ways. If we set the same densities on the inkjet as
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on the press, and think of that as color management, then we're
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breaking the workflow.
That's why I mentioned giving the profile 'room', getting the right mix of
not going BELOW the measured densities (of the press or printing process we
are trying to simulate), and the visual appearance of the 'colors' on the
inkjet paper.
All this without effecting the ink/paper balance of 'shrinking gamut vs
boosting' you mention later in your post.
The actual 'calculation' for how far to 'limit' the densities of each
channel, and where to set the total ink for the inkjet (between the amount
the inkjet can print and the proofing or printing method we are trying to
match) is the $64,000 question . . .
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(Wrt CMYK profiles into CMYKcm output handled in the RIP, remember
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that for now ICC profiles are four channel partly because of issues
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over +4 channel file formats.)
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> 'Personally', I have found that setting the ink densities, and then the
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> total ink limits BEFORE building the profile, is actually 80% of the work
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> needed, and then how you build your profile (UCR/GCR - Black generation) is
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> the other 20% of the work.
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Of course, but you're looking at two different contexts. For the PS
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DesignJets, this is preset right out of the box. The third party
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proofing papers I'm playing with like MPA Sihl J35 (L97.5 a1 b-1 -:))
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also work fine with these presets.
I am looking at this primarily from using a third party rip (BEST in my
case), which I should have asked how Howard was getting his file from his
workstation, to the inkjet.
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If you have a third party RIP, the ink limiting is up to you. Which
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is why I wrote:
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> d. Density control comes before color control. Ink limiting is about
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> going high
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> to get the pure colors that outline the gamut volume, and not loosing detail
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> through spatial bleeding problems. Taking down the ink limit shrinks gamut
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> and boosts detail. Taking up the ink limit boosts gamut and shrinks
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> detail. Before'
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> the CMYK testchart is printed as deviceCMYK (no conversions anywhere), get
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> the ink limit right, and make it stay right.
I was responding to your comment "Don't tweak any densities, don't even
think of tweaking any Densities" - not to your "Inkjet profiling ABC" post
from back in January.
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> These were the first 'TWO' documents I read on profiling, and I am still
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> waiting on the 'THIRD' to be finished . . . ;)
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Well, it's finished alright, so I'll let Sweet Sue know you're waiting -:).
Let's go Sweet Sue ! ;)
Darrin.
PS: Howard - has ANY of this information been helpful ?