follow up results on "Lab in always just right"
follow up results on "Lab in always just right"
- Subject: follow up results on "Lab in always just right"
- From: "Vanderlinden, Thomas M." <email@hidden>
- Date: Thu, 13 Sep 2001 10:15:33 -0400
good morning - - - -
After some off list communications, exchange of pictures
and testing between Steve Upton of CHROMiX and myself,
we have found that the 3-D representation of the Lab space
as rendered by ColorThink is faulty when ColorThink uses
the Apple CMM, which is controlled by what CMM you select
in the ColorSync control panel.
This doesn't happen when the Heidelberg CMM is selected.
With the Heidelberg CMM, the reflective scanner profile
and the ink jet profile appear fully contained
by Lab's box-shaped space (it is not box-shaped
when the Apple CMM is used).
The Ekta Space and Adobe RGB 1998 spaces also appear contained,
although may just barely extend outside of the Lab box
at the very extreme tip of one or two color areas.
Thanks to Steve Upton for tracking this down.
I do not know if this means that the Apple CMM and ColorThink
have an incompatibility issue, or if the Apple CMM is flawed
and cannot always be counted on for correct color rendering.
Steve also pointed out that ONLY the Apple CMM
is available for use in OS X.
Thanks also to Terry Wyse who brought this whole subject up
by recommending the Lab space as a storage space
to convert to from scanner RGB.
versions used:
Macintosh G4 running OS 9.0
CHROMiX ColorThink 1.1
Apple ColorSync Extension 3.0.1
Heidelberg CMM 3.0.1
Agfa's ColorTune 3.0.1, which shows same behavior
as Heidelberg's on this issue
- - - Tom Vanderlinden
email@hidden
Bridgeport National Bindery