[argyllcms] Re: relativ volume of gamut -- vrml comparison?
- From: "Preben Soeberg" <prsodk@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 9 Jan 2008 22:24:29 +0700
On Jan 9, 2008 8:40 PM, Peter Karp <qmailing@xxxxxxxxxxxxxxxx> wrote:
> Could it be that the conversion with relative intent is the problem?
> In my understanding gamut comparisons are only meaningful with
> absolute intent, aren't they? Please correct me if I'm wrong or tell
> me in which situations relative intent would be "the right choice".
>
> If the two profiles have a different whitepoint this could be the
> reason, right? When I calculate the gamut of Adobe-RGB with absolute
> and relative intent I get different values, but if I calculate the
> gamut of ECI-RGB then I get (nearly) the same values for the gamut,
> because the target whitepoint of D50 is already the whitepoint of the
> profile itself:
Thank you Peter,
The (missing) white point calculation could be the explanation.
The matrix in the cameraprofile is a zero matrix, so a matrix
transformation is not possible for this profile, it can only use the
A2B1 table.
When converting to Adobe RGB, a white point calculation can be done again.
When we change our intent from abs col to rel col, the Adobe RGB gamut
shrinks about 8%,
And the combined 6071_F And Adobe RGB gamut shrinks about 7%.
Can that be the explanation?
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