[argyllcms] Re: Profile input white not mapping to output white

  • From: Gerhard Fuernkranz <nospam456@xxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 27 Nov 2012 09:54:19 +0100

Am 27.11.2012 08:14, schrieb Graeme Gill:
well, all input profiles are meant to render the chart white patch as D50 using 
relative colorimetric.

Hi Greame,

this make certainly sense if a specific medium is in the play which should be 
captured under fixed lighting conditions.

For camera profiling, it is IMO not so clear that the color and luminance of 
the white patch on a test chart has any specific meaning for the scenes which 
are eventually captured with the camera (particularly if the white patch does 
not even happen to be spectrally flat, as it is the case for some targets). I'd 
possibly be more liberal and give the users the choice to select the profile's 
media white point location freely, depending on their particular shooting 
scenario and/or workflow, in order that applying the profile with relative 
colorimetric intent will eventually clip at the desired white point.

[ This still does not solve any extrapolation issues of course, unless the 
chosen WP is inside the gamut of the target. Btw, which model do you use 
internally for extrapolation? -am, -ag, -aG ? ]

Best Regards,

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