RawTherapee

A RAW converter built around a real pipeline

RawTherapee is a 64-bit RAW converter and non-destructive photo processor for Windows, macOS and Linux, released under the GNU General Public License v3 or later. It opens RAW files from a very wide range of digital cameras as well as ordinary TIFF, JPEG and PNG images, and exports the finished result as TIFF, JPEG or PNG. The original capture is never rewritten. Every adjustment is kept in a small .pp3 sidecar profile stored beside the image, which means a photograph can be reopened months later and re-processed from scratch with nothing lost.

The important structural idea is that RawTherapee is not a layer-based pixel editor. It is an ordered processing pipeline. Each tool you enable sits at a defined point in that chain, and the order in which demosaicing, white balance, tone, colour and sharpening are applied is fixed by the engine rather than by you dragging panels around. Understanding that is the difference between fighting the program and getting clean results from it quickly.

The editing workflow

Work starts in the file browser, which shows a folder tree, a thumbnail grid and a metadata/filter pane. Thumbnails are generated the first time a folder is opened and then cached, so the initial pass over a large shoot is the slow one. Double-clicking a thumbnail opens the editor, where the tool tabs sit on the right: exposure, detail, colour, transforms, RAW, and the more specialised wavelet and local adjustment panels. The preview is rendered from the actual pipeline, not from an embedded camera JPEG, so what you see reflects the settings rather than the manufacturer's own rendering.

A typical session runs top to bottom. Set the working profile and demosaicing method in the RAW tab, fix exposure and black level, then shape contrast with the tone curve, then deal with colour, then noise and sharpening, and only last the local adjustments that touch selected regions. Saving writes the sidecar; it does not re-encode anything. When the same look needs to apply to a whole shoot, copy the profile from one image and paste it onto the selection, then push the selection to the queue.

Batch rendering, profiles and colour management

The queue is a second, independent stage. You choose an output format, bit depth, resolution, filename template and destination folder, then start the render; the queue can run in the background while you keep editing. Because profiles are plain files, a house look can be saved once and reused across projects, and the bundled command-line tool can apply a profile to a folder non-interactively, which is what makes RawTherapee usable in a scripted or partly automated workflow.

Colour handling is one of the areas where the program goes further than consumer converters. Input profiles for the camera, working profiles, monitor profiles and output profiles are all selectable, and DCP or ICC camera profiles can be supplied for camera bodies that need them. Film simulation is handled through external HaldCLUT images, so the set of available looks depends on the lookup tables you install rather than on a fixed built-in list.

Practical limits and settings worth knowing

RawTherapee leans on the CPU rather than the GPU, so a multi-core processor and plenty of memory matter far more than the graphics card, and a machine with modest RAM will slow down when many large files are queued at once. Cache and thread counts live in the preferences and are worth setting to match the machine before a big batch, since the defaults are conservative. Some operations, particularly heavy noise reduction and large-radius local adjustments, are visibly slower than in GPU-accelerated commercial converters, and preview updates on very high-resolution files can lag behind the sliders.

There is no catalogue, no keyword database and no cloud library. It has no layer stack, no masking brushes on the order of a retouching application, and no mobile or web companion. It also expects the user to understand what a working profile or an output gamma is; there is no guided mode that hides those decisions.

Who should choose something else

Pick a library-first tool such as digiKam or a commercial catalogue if the main problem is organising thousands of photographs rather than converting them. Choose GIMP, Photoshop or Affinity Photo when the job needs compositing, layers and pixel-level retouching. Choose a phone-style editor or a one-click preset app if you want a good result without engaging with a pipeline. RawTherapee rewards photographers who want control over the conversion itself and are willing to learn a fixed, ordered set of controls to get it.