Re: ProfileMaker Yellow problems
Re: ProfileMaker Yellow problems
- Subject: Re: ProfileMaker Yellow problems
- From: Lasse Seppälä <email@hidden>
- Date: Tue, 11 May 2004 11:11:37 +0300
Graeme Gill wrote:
>
> Lasse Seppdld wrote:
>
> This problem is build in Lab-colorspace (and therefore in all
>
> ICC-profiles, whether RGB or CMYK), as clearly stated on web-site of
>
> Bruce Lindbloom:
>
>
You are mistaken. Just because ICC profiles can use L*a*b* as a PCS,
>
doesn't mean that they inherently suffer from issues caused when
>
gamut mapping in L*a*b* space. There is a difference between
>
storage space (ICC profiles using XYZ or L*a*b*) and computation
>
space (any space you can convert XYZ or L*a*b* into, which means
>
almost any colorspace ever invented, or being developed).
Firstly: I am not a color scientist, just an ordinary end-user (albeit
lurking under the hood more often than some), and make sometimes fairly
straightforward conclusions (it was not fair to say all profiles
suffer, technically you described the difference); appreciate your
corrections and other information. The site of Bruce Lindbloom just
simply explains the roots of problem, the ways to correct this issue in
profiling-sw are surely many and all manufacturers use their own
specific means.
The problem with oversaturated blue,yellow and red still exists with
many profiles (the poor end users must fight with it daily and is quite
irritating to explain it non-existent, as Gretag tech support did for
Laura Rimbaud), the correction of hue shifts is in many cases clearly
not enough or not equal with different source profiles. As Graeme Gill
explained few posts earlier, it may be not even possible to get good
match with some source-destination pairs without manual compensation
(it is not so complicated to selective correct hue-angle and play with
saturation/lightness).
Does anybody know, what is the source profile assumption for
ProfileMaker gamut mapping?. I really liked the approach ColorSynergy
had for profile creation: you could select also the source profile for
calculation (that is of course also a limitation, but with correct
source the results were fine). Personally I have experimented with
working spaces, that are based on colors from destination space
(usually working spaces are derived more or less from monitors). Hue
problems diminish and you can get all of the source profile, but this
workingspace is not for general use.
ls
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