RawTherapee is a powerful, cross-platform raw photo processing system, released as Free Software. It is designed for developing raw files from a broad range of digital cameras and targeted at users ranging from enthusiast newcomers who wish to broaden their understanding of how digital imaging works to professional photographers.
RawTherapee provides a powerful suite of tools for you to produce amazing photos and showcase your creativity.
RawTherapee is one of two open-source applications that attempt to duplicate the functionality Adobe’s LightRoom the second being Darktable. Both are very similar to LightRoom but I think RawTherapee might be better. To be fair to Darktable I tried it many years ago. At the time I thought it was buggy but it might be fine now. I’ll have to try it again.