Re: D65 exported data
Re: D65 exported data
- Subject: Re: D65 exported data
- From: "dpascale" <email@hidden>
- Date: Mon, 1 Jun 2009 20:23:08 -0400
Hello Mike,
If you compare Lab D50 vs Lab D65 (not spectral data), then the first set of
differences makes sense, assuming that a proper Bradford transform was made
betwen the two data sets, so that they are compared under the same
Illuminant (either D50 OR D65).
This is the Illuminant metamerism. (or Color Inconstancy, to be more
specific), since the Bradford transform simulates a perfect match between
Illuminants, which is different from the actual perceived value computed
with the spectral data (i.e. your initially exported data which combines the
Illuminant spectra and the target spectra).
However, I do not understand what exactly you are comparing in the second
case.
.
Please send me the file and the steps you do in the second part.
Thanks,
Danny
www.babelcolor.com
----- Original Message -----
From: "Mike Eddington" <email@hidden>
To: <email@hidden>
Sent: Monday, June 01, 2009 5:42 PM
Subject: D65 exported data
I was comparing Lab measurements exported out of Profilemaker MeasureTool
ast both D50 and D65, then attempted to do the same within a ColorThink
worksheet from a single spectral data set, but got vastly different
results. I would expect to get the same results.
In the first instance I open a spectral measurement file in MeasureTool
and exported both D50 and D65 Lab values, then dropped in a Colorthink
worksheet and compared them
Next, I dropped the spectral file in a worksheet, then dropped the same
measurement file again, and changed the Color setup to CIEstdD65 (6430K)
and compared. I was expecting near the same delta values as in the first
method.
There appears to be a major difference between D65 out of MeasureTool and
CIED65 (6430) in Colorthink..babelcolor patchtool have slightly different
result to mesuretool.
.anyone care to comment?
Results below:
Exported from MeasureTool and compared in ColorThink:
--------------------------------------------------
dE Report
Number of Samples: 1617
Delta-E Formula dE76
Overall - (1617 colors)
--------------------------------------------------
Average dE: 1.49
Max dE: 3.70
Min dE: 0.00
StdDev dE: 0.82
Best 90% - (1454 colors)
--------------------------------------------------
Average dE: 1.32
Max dE: 2.61
Min dE: 0.00
StdDev dE: 0.69
Worst 10% - (163 colors)
--------------------------------------------------
Average dE: 2.95
Max dE: 3.70
Min dE: 2.61
StdDev dE: 0.27
--------------------------------------------------
Calculated D50 and CIEstdD65 within Colorthink and compared
--------------------------------------------------
--------------------------------------------------
dE Report
Number of Samples: 1617
Delta-E Formula dE76
Overall - (1617 colors)
--------------------------------------------------
Average dE: 10.07
Max dE: 16.69
Min dE: 4.20
StdDev dE: 2.84
Best 90% - (1454 colors)
--------------------------------------------------
Average dE: 9.50
Max dE: 13.92
Min dE: 4.20
StdDev dE: 2.39
Worst 10% - (163 colors)
--------------------------------------------------
Average dE: 15.10
Max dE: 16.69
Min dE: 13.96
StdDev dE: 0.81
Mike
--------------------------------------------------------------------------------
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