[argyllcms] Re: spec2cie

  • From: Joe Tschudi <tresorjoe@xxxxxxxxx>
  • To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
  • Date: Sun, 15 Sep 2013 08:03:54 +0200

Hello,

Does anyone have any idea about how to solve this issue?

Thanks, Joe


Am 04.09.2013 um 15:06 schrieb Joe Tschudi <tresorjoe@xxxxxxxxx>:

> Hello,
> 
> I am getting weird results out of spec2cie when converting spectral data to 
> CIE data by using a custom illuminant. First I tried spotread (spotread -v -s 
>  -c1 -a CustomTest_spotread.sp) to get ambient emission curves to be saved as 
> an .sp file. I also tried illumread (illumread -v -c1 
> CustomTest_illumread.sp) but the results after converting with spec2cie are 
> even further off.
> I have spectral remission data that I measured using the same device (i1Pro 
> 2) with chartread (chartread -v -c1 -p -L -S TEST) which I am trying to 
> convert from spectral data to LAB using the custom illuminant with spec2cie 
> -v -n -i CustomTest_xxx.sp spectral.ti3 cie.ti3
> 
> Although the CCT of the emission curves shows me a value of around 5850K I am 
> getting LAB results that are completely blueish and have nothing to do 
> anymore with the original spectral color. To compare the results I am using 
> Bruce Lindbloom's Spectral Calculator Spreadsheets (10nm) 
> (http://www.brucelindbloom.com -> Calc -> Spectral Calculator Spreadsheets -> 
> scroll down for 10nm Download) where it's possible to fill one custom 
> spectral (remission) column and a custom (emission) illuminant and the 
> results there are correct IMHO.
> 
> Using regular spec2cie with -i D50 I get:
> 2° LAB 91.21 / 0.15 / 4.34 
> 
> With the Spreadsheet I get:
> 2° CustomIlluminant_spotread: LAB  91.12 / -0.47 / 4.49
> 2° CustomIlluminant_illumread: LAB  91.04 / -1.12 / 4.50
> 
> With spec2cie I get:
> 2° CustomIlluminant_spotread: LAB 91.12 / -4.29 / -4.91
> 2° CustomIlluminant_illumread: LAB 91.04 / -12.35 / -20.10
> 
> Am I doing something wrong?
> 
> Attached I am sending the TEST.ti3 spectral remission data, both 
> CustomIlluminant_spotread/illumread.sp and the Spreadsheet of Bruce Lindbloom 
> to fill the r/emission data.
> 
> Thanks for your help in advance if you can provide any.
> 
> Best regards,
> Joe Tschudi
> 
> <TEST.ti3>
> <CustomTest_illumread.sp>
> <CustomTest_spotread.sp>
> <SpectralCalculator10nm.xls>

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