Kai-Uwe,
Just take the ICC profile as a black-box. The fact some profiles
are implemented as matrix-shaper should be irrelevant.
If you understand primaries as the chromaticity of colorants,
obtaining the primaries should be as easy as using an absolute colorimetric
transform from the given profile to XYZ space, and then obtaining
the XYZ value of each colorant. This will work on all colorspaces,
not only on RGB.
Regards,
--
Marti Maria
The littlecms project.
www.littlecms.com
----- Original Message -----
From: "Kai-Uwe Behrmann" <[EMAIL PROTECTED]>
To: "Lcms Liste" <lcms-user@lists.sourceforge.net>
Sent: Thursday, October 06, 2005 8:01 PM
Subject: Re: [Lcms-user] ICC profiles -> primaries
Hi,
even in danger to repeat this toppic, here comes my own take:
The primaries stored in the rXYZ,gXYZ and bXYZ tags are part of the
RGB<->XYZ conversion matrix. They are related to D50.
The whitepoint in wtpt represents the original whitepoint of the media.
To convert from D50 primaries to oroginal wtpt primaries the chad tag was
introduced. It holdes the conversion matrix to come from D50 primaries to
wtpt primaries.
Additional the chromaticity (chrm) tag, natively being in wtpt, can be
used to hold the origin in the profile.
Without knowing the chromaticities (chrm) or the transform (chad)
conversion is guessing of the right transform. Bradford is a good
candidate.
The good news, now I understand it, the chrm tag is included by lcms
during RGB matrix profile generation. Thanks!
regards
Kai-Uwe Behrmann
+ development for color management
+ imaging / panoramas
+ email: [EMAIL PROTECTED]
+ http://www.behrmann.name
Am 03.10.05, 12:38 +0200 schrieb Kai-Uwe Behrmann:
Hi,
is there a example to get the real xy primaries from an given matrix
profile, including white point adaption?
regards
Kai-Uwe Behrmann
+ development for color management
+ imaging / panoramas
+ email: [EMAIL PROTECTED]
+ http://www.behrmann.name
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