Hi,  I'm new to Color profiles and lcms, and wonder if you can help me
understand how to grab spot color information from a TIFF file
correctly.

In Photoshop, I set the spot color swatch to a particular CMYK value.
When I parse the TIFF, I see it's in the CIELab colorspace.

So far, I've been able to get the profile out of the TIFF:

   if (TIFFGetField(tiff, TIFFTAG_ICCPROFILE, &EmbedLen, &EmbedBuffer))
   {
      printf("we have an ICCPROFILE\n");
      hProfile = cmsOpenProfileFromMem(EmbedBuffer, EmbedLen);
      if (hProfile == 0)
      {
         hProfile = OpenStockProfile(cDefInpProf);
         printf("but we couldn't read it.\n");
      }
   }

And I've also been able to get the Lab color out of the Photoshop
binary block within the TIFF. I'm grabbing the irb_word 0x3EF and
seeing:

cs: 7 Lab: 0x0763 0x1315 0xDFB9 0x0000 alpha: 0064

I can see from the lcms tiff example that I have to unpack the Lab values...

But what I'm not seeing is a call in lcms to transform this Lab to
CMYK.  I need the CMYK because I'm converting the TIFF with spot
colors to PDF.

Do I need to create a second default color profile, and then a
transform between the two?  I want to avoid creating whole LUTs,
because in the worst case I'll only have a few Lab colors to convert.

Thanks!

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