Re: ProfileMaker Yellow problems
Re: ProfileMaker Yellow problems
- Subject: Re: ProfileMaker Yellow problems
- From: Graeme Gill <email@hidden>
- Date: Tue, 11 May 2004 12:08:53 +1000
- Organization: Color Technology Solutions
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).
For developers there is also a kind of solution (and more info) in a
form of "Uniform Perceptual Lab Profile" for download (/info/Uniform
Perceptual Lab Profile), somebody really using it?
There are many other possible solutions. All current work on Color Appearance
Spaces (CAMs) have the aim of addressing the well known (amongst Color Scientists)
issues off having a good match between numerical and perceived constant hue.
Correcting L*a*b* hue issues with a correction table is one simple
approach (See "Color Gamut Mapping in a Hue-Linearized CIELAB Color Space"
by Gustav J. Braun and Mark D. Fairchild, IS&T/SID 6th Color Imaging Conference, Scottsdale, 1998,
<
http://www.cis.rit.edu/people/faculty/fairchild/PDFs/GusCIC98.pdf> for the
definitive information on that approach.) Notice that that is from
a few years ago. Most current research seems to be based around using one of the
standard CAMs such as CIECAM97 or CIECAM02. How much of this has penetrated
commercial Color Management Systems is yet to be seen.
Graeme Gill.
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