AW: profiling deeper colors
AW: profiling deeper colors
- Subject: AW: profiling deeper colors
- From: Samer Mady <email@hidden>
- Date: Thu, 13 Dec 2001 10:01:36 +0100
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How does profiling software handle colors deeper than swop,
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IOW not really
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cyan but bluer than cyan in inkjet printers?
each output device can physically reproduce a limited amount of colors; the
saturation and density of the primary colors of the output device determine
the boundary of the gamut. if the gamut of the destination profile does not
encompass all colors of the source profile it is necessary to have an
algorithm for mapping between the two gamuts ( such algorithms are called
gamut mapping algorithms ) the aim of gamut mapping algorithms is not an
accurate reproduction of individual colors but to ensure a good
correspondence of overall color appearance between source and destination
profiles. there are many different gamut mapping algorithems. the icc
defines four gamut mapping algorithms: relative colorimetry, absolute
colorimetry, perceptual and saturation intent.
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Situation: My rip software can control ink limits in 3 areas;
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1)light cyan, 2)
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regular cyan and 3)combination C-lc to produce a deeper color
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than 100% cyan.
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I've tried setting up 100%C with a percentage of lc for 2
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reasons, one is to
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increase ink density and the other was to increase gamut.
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I'm coming to the
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conclusion that this setup does not work very well. My HP
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5000 profiles work
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very well with very little lc added to C, a gamut larger than
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my matchprint
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profile. My Arizona with large amounts of lc added to C
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produces a profile
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that washed out mid to shadow transitions in blues and reds
the advantage of lc is that you can have s smooth gradation in the light
areas. if you have only norm cyan you see the donts in the light areas.
becouse of the low density of lc it does not increase the density or the
saturation of the colors.
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(M is set up the
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same way) and gamuts less than the matchprint. The first
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profile I made
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worked but the image looked washed out, therefore my
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reasoning for increasing
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the 100% ink densities. Since then, the profiles have been trouble.
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I use Profile maker and have tried several combinations of
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GCR/UCR. Viewing
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the profiles in Colorthink doesn't give any indication
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something would be
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wrong, even white points seem normal, no uv problems.
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Opinions please?
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Pete Merck
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