Re: some thoughts on CIELAB
Re: some thoughts on CIELAB
- Subject: Re: some thoughts on CIELAB
- From: Roberto Michelena <email@hidden>
- Date: Sun, 09 Feb 2003 16:14:45 -0500
>
After the mapping of the color is done, simply convert to the Lab PCS
>
and stick it in the ICC profile table. Profiles made this way will not
>
suffer the problems caused by the so-called "flaws" of Lab.
Is this really true?
I guess it would take a really complex CMM to do its interpolation in any
other space than Lab or XYZ, given that the table is handed to it in one of
those spaces. And by doing interpolation in a space which isn't perceptually
uniform (in which distances mean different things depending on where you
are!), and moreover whose perceptual curvature can reach higher orders than
the interpolation's order, and whose deformities are different for different
parts of the color space...
If such a CMM were to exist that makes use of a third space for
interpolation, still the table grid is defined in either Lab or XYZ, leading
to uneven sample density (and possible holes) in such third space.
And it would need, in the same fashion current profiling packages have, a
dictionary (better said, map) of Lab space quirks so as to special-case each
point depending on which zone it lands on.
Well, throw in a 7-color pigment-based inkjet, in which to make things worse
black is not neutral, and no wonder you get crossovers in neutrals and
contrast losses or exageration in chromatic colors. Unless you take the
countless hours that Bill Atkinson took to make his profiles.
It's the interpolation that worries me, not the representation of the grid
points. What should one have, a 48- or 64- grid profile?
-- Roberto Michelena
EOS S.A.
Lima, Peru
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.