RawTherapee

Input file formats

RawTherapee supports most raw formats, including Pentax Pixel Shift, Canon Dual-Pixel, and those from Foveon and X-Trans sensors. It also supports common non-raw image formats like JPEG, PNG and TIFF.^[6][7] It also supports high dynamic range, 16/24/32-bit raw DNG images.

RawTherapee uses a patched version of dcraw code to read and parse raw formats, with additional tweaks and constraints to parameters such as white levels and the raw crop area based on in-house measurements. Thus, RawTherapee supports all the formats supported by dcraw.

User interface

RawTherapee provides the user with a file browser, a queue, a panel for batch image adjustments, a 1:1 preview of the embedded JPEG image in the case of raw files, and an image editing tab.

The file browser shows photo thumbnails along with a caption of the shooting information metadata. The browser includes 5-star rating, flagging, and an Exif-based filter. It can be used to apply a profile, or parts of a profile, to a whole selection of photos in one operation.

A toolbox alongside the file browser allows for batch image adjustments.

The queue tab allows one to put exporting photos on hold until done adjusting them in the Editor, so that the CPU is fully available to the user while tweaking a photo, instead of processing photos while the user is trying to tweak new ones which could result in a sluggish interface. Alternatively, it can be used to process photos alongside tweaking new ones, if one has a CPU capable of handling the workload.

The Editor tab is where the user tweaks photos. While the image is opened for editing, the user is provided with a preview window with pan and zoom capabilities. A color histogram is also present offering linear and logarithmic scales, and separate R, G, B and L channels. All adjustments are reflected in the history queue and the user can revert any of the changes at any time. There is also the possibility of taking multiple snapshots of the history queue, allowing for various versions of the image being shown. These snapshots are not written to the sidecar file and are subsequently lost once the photo has been closed, however work is underway on migrating the PP3 sidecar system to XMP which already supports storing snapshots.

Adjustment tools and processing

• The following Bayer demosaicing algorithms are available: AMaZE, IGV, LMMSE, EAHD, HPHD, VNG4, DCB, AHD, fast or mono, as well as none.^[8]. Raw files from X-Trans sensors have the 3-pass, 1-pass and fast demosaicing methods at their disposal.
• Processing profiles support via sidecar files with the ability to fully and partially load, save and copy profiles between images.
• Processing parameters can be generated dynamically based on image metadata using the Dynamic Profile Builder.
• Exposure control and curves in the L*a*b* and RGB color spaces.
• CIECAM02 mode.
• Advanced highlight reconstruction algorithms and shadow/highlight controls.
• Tone mapping using edge-preserving decomposition.
• Pre-crop vignetting correction and post-crop vignetting for artistic effect.
• Graduated filter.
• Various methods of sharpening.
• Various methods of noise reduction.
• Detail recovery.
• Removal of purple fringing
• Manual and automatic pre- and post-demosaic chromatic aberration correction.
• Advanced wavelet processing.
• Retinex processing.
• White balance (presets, color temperature, spot white balance and auto white balance).
• Channel mixer.
• Black-and-white conversion.
• Color boost and vibrance (saturation control with the option of preserving natural skin tones).
• Hue, saturation and value adjustments using curves.
• Various methods of color toning.
• Lockable color picker.
• Wide gamut preview support on Windows and Linux, while the macOS preview is limited to sRGB.
• Soft-proofing support.
• Color-managed workflow.
• ICC color profiles (input, working and output).
• DCP color profiles (input).
• Support for Adobe Lens Correction Profiles (LCP).
• Cropping, resizing, post-resize sharpening.
• Rotation with visual straightening tool.
• Distortion correction.
• Perspective adjustment.
• Dark frame subtraction.
• Flat field removal (hue shifts, dust removal, vignetting correction).
• Hot and dead pixel filters.
• Metadata (Exif and IPTC) editor.
• A processing queue to free up the CPU during editing where instant feedback is important and to make maximal use of it afterwards.

Output formats

The output format can be selected from:^[9]

• TIFF (8-bit and 16-bit)
• JPEG (8-bit)
• PNG (8-bit and 16-bit)

v2 series

Version 2.4.1 was released in September 2009; the last closed source version released. Since then RawTherapee has become open source (it was closed before 2010) and a number of developers have joined the project, adding new features and improving stability.

v3 series

The 3 series with version "Dev-3.0" was the first to be released as open source. Major changes incorporated in this series include:

• New licensing: RawTherapee is now released under the GPL licence.
• New interface layouts possible offering more efficient screen space usage. Separate file browser and processing queue tabs. A choice between "single tab filmstrip mode" and "multiple tab mode", both with the possibility of having the tabs positioned vertically.
• Ability to open multiple images simultaneously.
• New preview logic. Faster and smoother zooming and panning. Smoother preview image.
• Numerous new filters and demosaicing algorithms.

4.0 series

Version 4.0.0 was released on 2011-07-30, leading up to the release of version 4.0.12 on 2014-01-07 which concludes the 4.0 series.

Major changes incorporated in this series include:

• New engine, all processing takes place in 32-bit floating point for high precision.
• UI is improved and more customizable.
• New image processing tools, like black point compensation, new highlight recovery methods, automatic distortion control on Four Thirds system cameras, flat field correction, dark frame subtraction, etc.
• Improved color management, with high precision custom profiles created for some cameras specifically for RawTherapee.
• CIE Color Appearance Model 2002 implementation.

Because of the higher RAM requirements of the 4.0 version, though 32-bit operating systems are still supported, 64-bit machines are highly recommended for performance and stability.^[10]

4.1

RawTherapee 4.1 was released on 21 May, 2014.^[11]

4.2

RawTherapee 4.2 was released on 24 October, 2014.^[12]

5.0

RawTherapee 5.0 was released on 22 January 2017.^[13] There are two variants tagged as 5.0: one uses GTK2, and the other GTK3. Both variants are identical in every way except for the graphical toolkit.

RawTherapee 5.0-r1 was released on 2 February, 2017. This revision is functionally the same, but includes a few bug fixes which came to light after the 5.0 release.^[14]

5.1

RawTherapee 5.1 was released on 15 May 2017. Major new features include Pentax Pixel Shift support, the Dynamic Profile Builder and a dedicated command-line executable to reduce loading times for CLI users.^[15]

5.2

RawTherapee 5.2 was released on 23 July 2017^[16]. New Features since 5.1:

• GIMP plugin to open raw images in GIMP using RawTherapee.
• "Remote" mode (-R command line option) to allow opening images ("Open with" or passed as arguments) in a full-fledged instance. The -R mode allows you to open an image in an already-running instance of RawTherapee, if that instance was also started using -R. Opening an image without the -R option will open RawTherapee in "no-File-Browser" mode which lacks the File Browser and Queue tabs, and the Preferences button.
• Added DCP profiles for accurate color for Fujifilm X-T20.

5.3

RawTherapee 5.3 was released on 30 September 2017^[17]. New Features since 5.2:

• CIECAM02 enhanced with control over the scene and viewing conditions.
• CIECAM02-friendly "Average Surround" color theme and L* middle gray preview background color, takes into account human vision and color appearance with regard to the surrounding color.
• Manually save the collapsed/expanded state of tools.
• Lensfun support, for automatic (and manual) profiled lens correction.
• ACES, DCI-P3 Theater and DCI-P3 D65 output color profiles.