Re: D65 exported data
Re: D65 exported data
- Subject: Re: D65 exported data
- From: Steve Upton <email@hidden>
- Date: Mon, 1 Jun 2009 22:14:35 -0700
At 9:42 PM -0400 6/1/09, Mike Eddington wrote:
>
>My intention was to compare only values derived from spectral data. The second case I was attempting to do this using ColorThink. Rereading my post, it isn't that clear. Basically I dropped the same spectral data twice into a single worksheet (where I would get no delta if I compared), and changed the color set up on the second color list to CIED65, the enabled delta to compare.
>
>I'm away from my files, so I can't send them to you now, but will when I can. If you have any spectral data and color think, you should be able to see what I'm talking about though.
>
Hi Mike,
I think I can speak to some of the differences you are seeing.
When exporting Lab values from MeasureTool you are getting "raw" D50 and D65 flavors of Lab, as expected.
When they are imported into ColorThink (or any other compare tool, probably) they are treated as if they are the same flavor of Lab and delta-E is calculated. As far as I know, this is not correct.
ColorThink calculates D50 and D65 as requested and then the D65 values are adapted back to D50 for the dE differencing calculations. As a result you will also see the "D65" values in ColorThink are different than what you might see in another tool. They are post-adapted values. In this manner the dE calcs reflect the correct comparison (D50 -> D50) and the numbers "make sense" on screen.
To be honest, this is off the top of my head. I believe that this is the way it was designed and implemented. I haven't tested it recently to confirm that it's working as expected.
I hope this sheds some light on the behaviors
regards,
Steve
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