Re: [Lcms-user] Lab to sRGB

[Ignacio Ruiz-de-C. <ign...@si...>]

Martin:

> I'm trying to create a transform of Lab D50 values to sRGB, using
> Guy's python bindings and lcms 1.18a.

I wonder why you need to go through the D65 space... instead of
creating a single transform
Try this

    import littlecms as lcms
    import numpy as np
    labD50Profile = lcms.Profile(colourSpace=lcms.PT_Lab)
    sRGBProfile = lcms.Profile(colourSpace=lcms.PT_RGB)
    labD50_to_sRGB_transform = lcms.Transform(labD50Profile, sRGBProfile,
       renderingIntent=lcms.INTENT_ABSOLUTE_COLORIMETRIC,
inputDepth=0, outputDepth=8)
    labD50Colours = np.array([ [95, 0, -2], [55, -37, -50], [48, 74,
-3],[89, -5, 93]], dtype=np.float64)
    sRGBColours = labD50_to_sRGB_transform.doTransform(labD50Colours)
    print sRGBColours

and you will obtain
[[240 240 244],    [  0 151 218] ,   [217  23 122],  [252 222   6]]
which is close enought (+/- 1 count) to yours expected values
[239,241,245], [0,151,218], [216,11,122], [248,224,0]

Ignacio

-- 
______________________________________________________________
Ignacio Ruiz de Conejo
Senior Imaging Researcher
Tel.  : +61 28875 9682
e-mail: ign...@si...
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