babl master is now able to express CMYK based pixel formats backed by lcms2 and ICC profiles and most conversions that is needed by GEGL. The work mentioned in the previous post about making GEGL as a compositor less tied to RGB, and share a common code-path for 1, 3, 4 or more components in the case of spectral data is bearing fruit and for these operations CMYK support is now coming to GEGL.CMYK support is getting ready for GIMP. You can support the author on Patreon
GEGL can now work as a basic RGB-to-CMYK converter, as long as you have your target CMYK ICC profile
permits the following to work to convert an RGB image to
16bit integer tiff with the desired ICC profile:
This will also work for a file loaded with a CMYK ICC profile that has been
"demoted" to RGB at some point in the chain.
Read more : https://gitlab.gnome.org/GNOME/gegl/commit/6f4f5f9441b3c8e1ffc9da5f74022ec5236cae2c