Hi,
I have a question about using Bruce Lindbloom's UP Lab color space
with lcms. I would like to convert images with embedded profiles into this
space, do some manipulations, and then back again to write the output
files.
The profile for UP Lab has device class "ColorSpace". The A2B0 tag has the
CIELab to UPLab transform, and the B2A0 tag goes from UPLab to CIELab.
Stop me if I'm going astray... I've been poking in the source code for
cmsCreateProofingTransform and cmsCreateMultiprofileTransform to see if
they will give me a transform from the input color space to Lab and then
to UPLab, but it seems they won't.
Say for example the input space is sRGB. If I make a transform with the
input profile=sRGB and the output profile=UPLab, I'm guessing it is going
to go from sRGB -> PCS and then it's going to want to use the B2A0 tag in
the UP Lab profile to go from the PCS to the output space. Which is
backwards. I think I need a "transform-and-a-half", that is to say
sRGB->Lab and then Lab to the PCS of the UPLab profile.
I expect there is a good reason why Lindbloom's profile has UP Lab where
the PCS usually goes and regular Lab where the output usually goes. But I
don't understand what it is. Can someone tell me the right way to do this?
Thanks,
Andrew
---------------------------------
Andrew Mihal
www-cad.eecs.berkeley.edu/~mihal
[EMAIL PROTECTED]
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