Re: ICC and Colorspaces
Re: ICC and Colorspaces
- Subject: Re: ICC and Colorspaces
- From: email@hidden
- Date: Wed, 6 Dec 2000 08:50:45 EST
In a message dated 12/5/00 5:06:20 PM, email@hidden writes:
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My adventure with profiling to date has been less than successful, though
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I do see some light at the end of the tunnel which is what keeps me
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crawling on. I've invested in a Mc7 monitor calibrator and WiziWYG. The
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printers I'm trying to calibrate are all photographic (Pictrography, Fuji
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Frontier, KodakLED) and all RGB. My monitor is a Mitsu-1010e
The high end program using the same color core as Wizi (Previous versions of
Compass Profile) has been the preferred software for profing such devices, at
least until recently. But even with the highend stuff, and a
spectrophotometer, I often hear the same complaints as with Wizi: color casts
(usually green) and clogged shadows. I find ProfilerRGB does a better job to
begin with, and then offers editing capabilities if you still need to tweak
the profile.
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1) What kind of RGB working space is recommended when outputting to
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this kind of RGB printer which offers a larger color gamut than CMYK
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(which I view using BruceRGB)?
Ideally CMYK has nothing to do with this, unless you are dealing with press
output as well. Just use AdobeRGB; Bruce holds no real advantages over it,
and is non-standard. I find that the saturated colors I was blaming on RGB
space limitations are actually being clipped by the profilng process; I can
get much brighter vector colors by using the spectro based version of
ProfilerRGB (Called ProfilerPro) and a spectrophotometer to profile RGB photo
printers, and by using the Saturation intent with these ProfilerPro profiles.
Great photo colors, plus saturated vector colors... amazing. More complex
(LUT based) workingpsces and other voodoo can add a couple more percent to
the vector color saturation, but just running through AdobeRGB to ProfilerPro
with Satauration intent gets more color than any previous combination I've
seen on LightJets, Lambdas, Fujis etc...
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2) Will soft-proofing such a profiled RBG image in Photoshop6 be
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affected by the choice of this RGB colorspace and can this be a source
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of off colour prints?
Soft proofing will not affect output, unless you color correct while viewing
the soft proof. I find I can get excellent RGB softproofs from PS6, but there
needs to be some adjustments to proofing white and black points for using the
absolute return, especially for profiling backlit film!
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3) I've discovered an interesting "profile editing kludge" with WiziWYG.
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I
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can use Photoshop to select and alter the sample color swatches which
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were scanned together with the IT8 target print and then run this
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"doctored" version through the profiling software. This appears to be a
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cheap way to "edit" the profile. If a print comes out too yellow in the
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midtones then I just select the color swatches in the scan and add a
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similar amount of yellow to the midtones. When passed through the
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WiziWYG profiling software the result is a profile with less yellow in
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the
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midtones. Anyone else having any success with this kind of cheap editing?
Yes, I experimented with this back when Wizi first came out, and even posted
a few pieces about it, but using the editing sliders in ProfilerRGB is a much
more effective way to get this type of adjustment.
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4) If I want to profile a postscript printer (such as a Xerox color copier),
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should Postscript Color Management be turned on or off when printing the
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color swatch target?
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Off, definately...(consider PostScript color management a dead dinosaur,
Adobe may actually get around to burying it before too long <G>) but WiziWYG
only offers a single black conversion, which is likely to be very far from
what your color copier needs; its optimized more for inkjets, but is a guess
even there. ProfilerCMYK (sibling to ProfilerRGB) is the only affordable
package that offers serious black generation, UCR, GCR, UCA and toner limit
controls. I find that it can be used quite effectively with color copiers,
with results that are directly related to the quality of the copier... a good
profile on a lousy copier won't show much improvement as there are few levels
of color to begin with. Copiers need to be reprofiled regularly, so a fast,
easy to use program like ProfilerCMYK takes some of the pain out of this
repetition. End of commercial. <G>
You haven't really described what your problems are, so its a bit difficult
to address them...
C. David Tobie
Design Cooperative
email@hidden