Re: Absolute vs Relative Colorimetry in the ICC Profiles?
Re: Absolute vs Relative Colorimetry in the ICC Profiles?
- Subject: Re: Absolute vs Relative Colorimetry in the ICC Profiles?
- From: Roger Breton <email@hidden>
- Date: Fri, 21 Sep 2001 16:26:49 -0400
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> Lastly, the ICC mandates on p.118 that the "coordinates of the output paper
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> be *adapted* to the PCS Illuminant"? Wouldn't that defeat the purpose of the
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> media white point data in the first place? Why wouldn't the Media White
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> Point be encoded in "absolute" terms?
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>
The media white point is the D50, 2 degree observer measurement of the
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paper. It is used by the CMM only for creating absolute colorimetry (i.e.
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"un-adapting" as explained above).
I understand that it would not be possible to "un-adapt" the relative
colorimetry otherwise. Thank's.
What is clear to me is that EQ1, EQ2 and EQ3 on p.118 are all using the
absolute D50, 2 degree observer measurement of the paper.
Then the sentence that reads "coordinates of the output paper be *adapted*
to the PCS Illuminant" is wrong. Because, the value of the paper is the
absolute colorimetric measurement D50/2 off my Digital Swatchbook or
Spectrolino, not an adapted value, if I understand you Bruce.
This logic is hard to decipher.
Roger Breton
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--
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Bruce J. Lindbloom, Pictographics Intl. Corp.