Re: Bogus White Point Tags in Monitor Profiles?
Re: Bogus White Point Tags in Monitor Profiles?
- Subject: Re: Bogus White Point Tags in Monitor Profiles?
- From: JWL <email@hidden>
- Date: Sun, 11 May 2003 10:52:34 -0700
Ian Lyons <email@hidden> wrote:
>
>
There is nothing wrong with the profiles. What you are seeing is Gretag and
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BasICColor choosing to 3adapt2 the media (display) white point profiles to
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the standard (at least it was) D50 white point. You will find that the
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actual RGB colorant values indicated for your display are also weird. They
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too have been adapted but this time so that the first adpation is
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compensated for. The profiles are accurate and your images will all display
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as they should and the profiles. I can recall Bruce Lindbloom explaining
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what you are seeing on an earlier occasion.
-- Thank you for your helpful response, Ian. But are we talking about
slightly different things (or am I just confused, a not unlikely
prospect...)?
I thought Bruce Lindbloom's comments were about OptiCal incorrectly adapting
(or not adapting) the *color primaries* of the profile. (I'm not at work to
check my digest archives, but that's what I recall) I assume ColorThink
shows these color primaries as the outer edge points in the 3D plot, and I
don't know if these values are whacked or not. What I'm seeing in ColorThink
is the profile *white point* being plotted at 5000 instead of the expected
6500K.
Besides, OptiCal profiles are not the ones which produce the incorrect
("adapted?") WP value.
Another part of why I'm asking about this -
Viewing 3D plots of the same CRT monitor calibrated/profiled at 6500 &
5000K, the 6500K one looks like basically the same shape & volume, just
"leaning" over toward that "bluer" white point. So the 6500K plot looks as
if it's very limited in the extreme yellows. This sort of makes sense.
(Interestingly, Monaco's profiles don't show this same-shape-moved-over look
- the volume seems to "grow" more organically toward the 6500K WP, resulting
in a different shape from the 5000K one)
This 'same-shape-moved-over' business is confusing: I have seen CMS
presentations where a 5000K WP profile (identified as 6500K) was represented
as much better than a (correctly tagged) 6500K one - "see how much bigger
the color space is for softproofing press work..."
Maybe Photoshop is wise enough (can software be wise?) to sort through this.
Logically, it just seems like trouble if I calibrate my monitor to 6500, but
the profiling software "adapts" that to 5000K. Does that mean Photoshop
"thinks" my monitor is 5000K? (I'm probably not understanding the mechanism
of adaption here)
Thanks for the help in sorting thru this.
Regards,
John
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