Re: monitor profile
Re: monitor profile
- Subject: Re: monitor profile
- From: Roger Breton <email@hidden>
- Date: Thu, 28 Feb 2002 08:00:08 -0500
>
You are 100% correct. Tom Beckenham was led astray by one of the most ill
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concieved and poorly documented parts of the ICC specification. The White
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Point in a monitor profile must always be D50 (The PCS specified white
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point). The Red Green and Blue XYZ tags are most definately NOT the XYZ
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coordinates of the Red Green and Blue Phosphor. One would expect that the
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White point tag and Colorant Tags might actually relate to the White point
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and Colorants, but that was not meant to be. The XYZ tags actually are the
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matrix which transforms the Colors in the monitor space to the D50 white
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point PCS. I have complained about this section of the spec from the day
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it was written. The adaptation method was never specified (although the
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"Wrong Von Kreis" transform was recommended at one point) so it was
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impossible to recover the actual display chromaticities from the profile and
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white point from the profile. The next generation specification has a tag to
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specifiy the adaptation method that is used. These tags carry an implied
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adaptation matrix and the original color temp and chromaticities can be
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deduced from the profile.
>
>
Tom Lianza
Tom,
If the monitor profile is "calibrated" at 5000K, then is it not possible to
interpret RGB XYZ tags as the XYZ coordinates of the Red Green and Blue
phosphors? I.e. There would not be any chromatic adaptation involved in that
case, would it?
Regards,
Roger Breton
Laval, Canada
email@hidden
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