Re: D65 exported data
Re: D65 exported data
- Subject: Re: D65 exported data
- From: Steve Upton <email@hidden>
- Date: Tue, 2 Jun 2009 09:08:51 -0700
At 11:33 AM -0400 6/2/09, Michael Eddington wrote:
>Thanks for all the information.
>
>Let me ask this question, what differences would one expect between D65 lab values derived from spectral data versus D65 values chromatically adapted from XYZ?
good question. The answer lies in metamerism. (illuminant metamerism specifically).
Basically adapting from one XYZ flavor to another ignores any spectral interaction between the illuminant(s) and the sample.
Calculating D65 with the D65 illuminant captures the effect of the illuminant on the sample. The difference is obviously important.
The term Metamerism in this case is used a little loosely but I'm OK with it :-) (others may not be). To be correct, this kind of calculation is part of determining metamerism with another illuminant measuring the same sample.
>For example, say someone is measuring sample with a handheld with D65 as the user defined illuminant, versus, spectral data exported out of MeasureTool , PatchTool or ColorThink. If someone were to set up a workflow for proofing and process control utilizing D65, what kind of issues could they potentially run into?
>
>So MeasureTool is deriving D65 from XYZ data rather than from spectral? Why then is this only an option when spectral data is present?
It uses the spectral data and gets D65-XYZ which is then converted into D65-Lab.
regards,
Steve
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