Gimp had been criticized for the lack of CMYK support. While there is
some truth until the full implementation of GEGL, Gimp can export into
CMYK with the use of plugin called Separate+. It is not perfect per se,
separate+ provide excellent tool to properly convert RGB to CMYK.
I was surprised that extension was not included in Fedora repository for
years. Spec file is available 
courtesy of OpenMamba should anyone interested to package it for
Fedora Project. Otherwise, I will step to port it.
Graphic& Web Designere