[argyllcms] Re: Custom illumination
- From: Gerhard Fuernkranz <nospam456@xxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 19 Jan 2010 18:26:41 +0100
Klaus Kompatscher wrote:
> Dear All
>
> Did try to create profile for custom illumination:
> - Measured light with I1 with special diffuser; Got measurements in cxf
> format (file attached)ite
> - Made a profile with Profile Maker White point looks good
> - Copied spectral values to ref. D50_1.5.sp file and renamed DalTile...
> (file attached)
> - made a profile ./colprof -v -i
> /Applications/Argyll_V1.1.0/ref/DalTileLichtI1.sp -kp 0 .3 1 1 .8 -r 2 -L
> 100 -l 280 G60_G07_5cc
>
> White point calculated by Argyll is fare off from the real.
> Visually it does not correspond at all.
> PM white point: Lab 87 0 2
> Argyll white point: Lab 88 5 30
>
I guess this is likely once again caused by different interpretations of
different profile vendors regarding how the the media white point should
be recorded in (V2) profiles; i.e. whether to record the absolute XYZ of
media white under the given illuminant versus recording the
illuminant-to-D50-adapted XYZ numbers. As long as the light source is
D50, there won't be a difference, but your light source is a different
one...
If my assumption is true, then visually I'd only expect a huge
difference for absolute intent, but I'd not expect so much difference
between the two profiles when applying them with relative colorimetric
intent.
Regards,
Gerhard
> I also tried to interpolate the spectral values to get 5 nm steps from 370
> to 730 but did not change anything.
>
> Why this big difference?
> What means Spectral_Norm in the Spectral illumination file?
>
> Thanks for any help
>
> Klaus Kompatscher
>
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