"Unstable version of GIMP is now capable of working in 16 and 32 bit per channel modes, both integer and float. Color management has been improved as well, and thanks to support by AMD and Google the GEGL library can do GPU-side rendering and processing with OpenCL."
http://www.gimp.org/
Kanske kan vara intressant att testa (är ju lite billigare än PS

Mvh
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