RawTherapee is a cross-platform app created by Gábor Horváth (and produced by the RawTherapee Development Team) specifically for processing (“developing”) digital raw photo files non-destructively and with high quality, keeping all changes in separate sidecar files and leaving the originals untouched. A history system lists all changes and lets you jump back to any previous step (or take a “snapshot” of a particular point in the editing process).

The app offers an extensive and impressive collection of features that includes support for raw files up to 32-bits, plus HDR DNG, as well as JPEG, PNG and TIFF; “advanced control over the algorithms with many fine-tuning parameters and curves”; multithreading for performance; floating point for precision; batch processing; a variety of demosaicing algorithms; many exposure and tone controls, as well as many noise reduction and detail enhancement options; batch processing; color profiles; and much more. (See RawPedia for more details.)

RawTherapee 5.8, the latest version, is free and open source software for OS X/macOS (probably 10.10 and later), Linux, and Windows.