I first noticed the news about improvement of the free open source GIMP with the major release of ver. 2.10.0 here:
https://www.dpreview.com/forums/post/61080227"Gimp 2.10 has been released. The big advantage for astrophotography is that Gimp 2.10 now has full support for 16-bit int and 32-bit float images. ... "
DPreview also has an announcement:
https://www.dpreview.com/news/7853845085/gimp-2-10-0-released-features-32-bit-support-new-ui-and-more (note that ver 2.10.0 is the successor to versions 2.9.x)
This could look like an interesting alternative for final image processing that needs some special editing, particularly for astro photo images. It is a very long time since I last had a look at GIMP and the user interface is a lot better than I remember. But I am sure there is a learning curve, especially for those of us who are not that into the logic of processing in Photoshop. I noticed some useful tutorials on the gimp.org pages.
It seems to be able to partly integrate with RawTherapee.
