[argyllcms] Re: input profiles -u and - U scale

There is white point issue with colprof & "-u" key for certain and specific 
target data: the profile works good inside ArgyllCMS with relative intent, but 
white point of characterized device is incorrect.
The same issue is with matrix profiles too: if the target data contains 
not-neutral patch which Y is highest, the profile is unacceptable.

Here is sample "RAW_daylight.ti3" in attachment. I'll send some more info to 
Graeme in private.

In my certain case the device WP is about 100,-1,1 Lab (WB was set on white 
patch of Digital Color Checker), but colprof gets as reference the patch with 
max Y and Lab 101,-12,31.

Wed, 09 Mar 2011 00:58:06 +1100 письмо от Graeme Gill <graeme@xxxxxxxxxxxxx>:

Nikolay Pokhilchenko wrote:
> Mention must be note, that in some cases (depends of spectral sensitivity of 
> the sensor
> and of the target reflection spectrum)  the lightest patch can be not white, 
> but green!
> And colprof can make a mistake in white point of the device because true 
> white patch
> has lower Y tan green patch.

I'm open to suggestions on what criteria would be more robust. Can you send
me an example .ti3 file of a case as you describe above ?

Graeme Gill

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