Re: [Lcms-user] Converting Lab to Lab values for different illuminants

[<mar...@li...>]

Quoting Martin Florek <mf...@gm...>:

> Hello,
> I would like to convert a D50 Lab values to Lab values for a different
> color temperature illuminant. Is this possible with Little CMS, and if
> then how? Tahnk you.


Hi Martin,

Yes, it is certainly possible.

- Create A D50 Lab profile by using

cmsCreateLab4Profile(NULL)

- Get the chromaticity of color temperature and use it as black-body  
white point

cmsWhitePointFromTemp(&White, temp);
cmsCreateLab4Profile(&White);

- Set adaptation state to unadapted

cmsSetAdaptationState(0);

- Then create the transform by using absolute colorimetric intent.

You can check this by using transicc:

C:\lcms2-2.6\bin>transicc -i*Lab -o*LabD65 -t3 -d0
LittleCMS ColorSpace conversion calculator - 4.2 [LittleCMS 2.06]

Enter values, 'q' to quit
L*? 100
a*? 0
b*? 0

L*=100.1896 a*=3.9640 b*=17.8366

Regards
Marti