Re: Is anyone getting better than a 3.0 DeltaE average on their Monitor profile?
Re: Is anyone getting better than a 3.0 DeltaE average on their Monitor profile?
- Subject: Re: Is anyone getting better than a 3.0 DeltaE average on their Monitor profile?
- From: email@hidden
- Date: Thu, 12 Jun 2003 09:17:14 EDT
In a message dated 6/12/03 9:06:55 AM, email@hidden writes:
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I am testing a whole slew of monitor profiles theses days, created with
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various instruments and profiling software.
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For my tests, I use Bruce Lindbloom's excellent Lab version of the Macbeth
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ColorChecker. I display that image in Photoshop 7 and measure each patch and
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compare with the source Lab value of the patch, as shown in the Info
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palette.
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So far, the best I've been able to accomplish is only an average of DeltaEab
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of 3.0. I wont't say with which profiling systems/instrument I got these but
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I am curious whether anybody else has ever tested their system that way
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(outside Bruce Fraser et al)? And what results are you getting?
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What bugs me is when I do the math manually from the profile adapted
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relative XYZ colorants to my monitor profile, all colors except the yellow
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and blue patch are in-gamut (DeltaE=0). But when I actually measure them,
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they don't correspond to the profile prediction? It can't be Photoshop, can
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it?
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I believe you will find that Monaco and Gretag Macbeth software use XYZ
scaling for whitepoint adaption, while ColorVision uses the Bradford Transform...
as does Photoshop, so the results between Photoshop and the ColorVision
profiles are consistant, while the results between the others and Photoshop are not,
as you have discovered. This bit of information is thanks to Bruce Lindbloom
as well.
C. David Tobie
Design Cooperative
email@hidden
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