Darktables

Darktables an open source photography workflow application and raw developer - now has potential Windows release

In reference to www.darktable.org/2017/08/darktable-for-windows/:

o cut a long story short, we are extremely pleased – albeit wary – to announce a very first official pre-alpha development snapshot for 64 bit Windows. We know it's still buggy, but as a sign of goodwill and request for help in testing it we would like to ask you to give it a try. Please report useful bugs in our bug tracker.