RawTherapee is a richly featured RAW file editor with versions for Windows, Mac and Linux. It is free, open-source software.
RawTherapee is a powerful, cross-platform raw photo processing system, released as Free Software (GPLv3). 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 benefits users who take the time to learn what it can do. Luckily the community is quite welcoming and helpful! Check out the Forum, read up on RawPedia, and ask questions – there’s always something neat to learn! 🙂
RawTherapee is Free and Open Source software. This means you can use it free of charge, wherever you like and however you like as long as you abide by the copyleft GPLv3 license.
https://rawtherapee.com/
It boasts high image quality, and support for a huge range of RAW formats, and documentation and an active support forum.