Re: Creating ICCs with pigmented inks
Re: Creating ICCs with pigmented inks
- Subject: Re: Creating ICCs with pigmented inks
- From: Chris Murphy <email@hidden>
- Date: Wed, 3 Jul 2002 09:31:35 -0600
Re: Creating ICCs with pigmented inks
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Sorry, this doesn't make any sense. There is no non-linearity
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involved. The light you see is the product of the reflectance
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of the ink and the intensity of the illuminant.
An illuminant is equated to a spectral power distribution curve - an
illuminant doesn't mean the same thing as a light source. There are
specific amounts of each wavelength in an illuminant. The light you see
is the product of both the spectral reflectance of the ink, the paper and
the spectral power distribution of the light source.
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One ink
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isn't more dependent on the illuminant, they are all completely
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independent of the illuminant.
Definitely not. If you have yellow ink on paper, and move to a location
where the light source has no emission in wavelengths between 590 and
630nm, that yellow ink isn't going to look very yellow. That's an extreme
example, but the color you get from ink is illuminant dependent. What we
see depends not only on the spectral reflectance of the ink + paper, but
the spectral power distribution of the light source to begin with.
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> The original Epson pigment inks don't match up well spectrally to press
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> inks at all.
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This is hardly a surprise. The aims, physics and economies of inkjet
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printers are rather different to presses. This will continue
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to be the case as manufacturers strive for wide gamuts etc.,.
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and is the reason why simple CMYK curves are not sufficient
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to make an inkjet emulate a press.
No, it's the reason why the color you get from these inks is so dependent
on what light source they are being viewed under at a given moment in
time. It doesn't matter what kind of color management you do - curve
based or table based.
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On the one hand you agree that only a tri-stimulus (aka metameric)
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match is possible, but on the other hand you complain
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that the spectral match is not good enough.
I said it would be nice to have a spectral match, but it's usually not
the goal (it's overkill), rather merely a colorimetric match was usually
the goal. I never said nor implied that only a colorimetric match was
possible and a spectral match wouldn't be good enough. If you had a
spectral match, then you would always have a colorimetric match
regardless of the illuminant.
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But this is exactly where manufacturers such as the one I work for
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add value. They aren't selling apps, they sell solutions. You
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don't have to understand how an Epson 10000CF can produce good
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(no, excellent) proofs, nor do you need the tools we use to
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achieve this, you just have to judge the results. We do the hard work.
Yes, fine, but I want to SEE the results of this effort with my own
eyeballs. Send me some samples!
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Now if you are doing it yourself, on the cheap, then yes,
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you have to use the tools that are available to you,
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and you might not be able to achieve comparable results.
Until I see hard samples of what you're able to produce, compared to all
of the "cheap" packages the rest of us schmucks have to use, I'm not
going to find repetitive sales talk very compelling. Pony up the samples!
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Love to, but I don't have a marketing budget at my disposal :-(
Wait a minute, you just said the manufacturer you work for sells
solutions. You can't sell solutions if you don't have samples of the
solution. We're talking about probably $1.00 in supplies, and some
postage. Come on, I want samples. Enough chit chat, I want to see
evidence. You're claiming your product will do things no other product is
capable of doing and yet you don't have a marketing budget for SAMPLES?
I'm not even asking for business cards or a brochure yet. I just want to
see an inkjet print. You guys have to have some of those just lying
around somewhere, just as a part of the natural development and product
testing process I would think.
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Bronzing is where the specular highlights (of the paper, not
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the image!) are colored by the ink. This is an effect seen in metal
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surfaces, and often the specular highlights have a bronze tint.
OK I can't say I've noticed this being a problem with pigment ink
printers and I haven't worked with Ultrachrome inks, so I will defer to
Andrew and Bruce if they have experienced this problem. Guys?
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On
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"normal" glossy surfaces, the specular highlights are the color of
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the illuminant.
Hey if you have paper substrates that can do that, I'd like to know where
to get some!
Chris Murphy
Color Remedies (tm)
Boulder, CO
303-415-9932
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