This page was first written in January 2023, right after the fork, and listed what had already diverged from darktable 3.8/4.0. A lot has happened on both sides since. The sections below summarize the major changes; the gory technical details live in the news section of the website.

What changed in Ansel since 2023

Performance and reliability

The pixel pipeline has been completely overhauled: modules run about 1.8× faster on CPU and 1.6× faster on GPU than darktable, and — more importantly — the pipeline cache was rewritten so that disabling a module, using a color picker or re-exporting an already-exported image does not recompute the whole thing. That makes Ansel 4 to 100× faster than darktable to refresh the image. Memory management was rewritten too: Ansel knows exactly how much RAM it uses and stays within the budget you set, instead of darktable’s hand-wavy “performance profiles” that have no predictability.

Lighttable, thumbnails and selection

The whole lighttable, thumbnail and mipmap-cache stack was rewritten. Concretely: starting the app and drawing a full collection is roughly 3.5× faster, switching between lighttable and darkroom is near-instant, and scrolling a large collection no longer stutters. The right sidebar was removed (its content moved to the global menu and the left panel), culling became the Restrict to selection filter, the filtering toolbar was rebuilt as plain inclusive toggle buttons, the zoomable lighttable came back (Columns + Zoom with barycentric auto-pan), and selection became explicit and What You See Is What You Get — no more metadata loss from a dangling mouse cursor.

GUI controls

The home-made Bauhaus sliders and comboboxes were largely rewritten: clicking the combobox chevron now works (imagine that), values are dispatched to the pipeline only when you stop dragging instead of on every intermediate step, and widgets redraw immediately for instant feedback even on slow machines.

Color tools

The color-grading tools were reworked so their color models are actually correct, rather than relying on broken assumptions papered over with magic numbers.

Masking

Drawn, parametric and raster masks are now independent, combinable toggles instead of a single exclusive mode. In particular, a raster mask can be combined on top of a drawn and/or parametric mask — see combining masks.

What darktable added that Ansel did not follow

darktable kept piling on features through versions 4.2 to 5.4. Ansel deliberately did not adopt most of them, either because they duplicate existing tools or because they don’t fit the design:

  • Sigmoid and AgX tone mappers — Ansel keeps a single, well-understood tone mapper (filmic). Bolting on two more display transforms that do the same job differently is exactly the kind of redundant clutter the fork exists to avoid.
  • Enlarge canvas and Overlay compositing modules — extending the canvas is handled by the framing module, and compositing several images is a job for a compositor, not a RAW developer.
  • Camera-specific “JPEG-matching” styles for 500+ camera models — chasing the out-of-camera JPEG per body is the opposite of a camera-agnostic, scene-referred workflow.
  • Multiple workspaces with separate databases — one library, kept fast, is enough.
  • The startup splash screen — a loading screen is a confession that startup is slow, not a feature. Ansel made startup fast instead.
  • The swap-sidebars preference, drag-and-drop utility-module headers, and the right-click “which modules to show” menu — Ansel removed the whole problem by moving button-only toolboxes into the global menu, so there is nothing left to rearrange.

Ansel does have its own color equalizer and color primaries modules, so those are not in this list.

What was removed from mainstream darktable

Features

The tethering view 
It relies on the lib GPhoto2 which is super brittle and buggy. The tethering view is merely a GUI over Gphoto2, much like Entangle . The problem is GPhoto2 is known to break something different at each new release, so it’s simply not worth the trouble to maintain a GUI over a Schrödinger cat. Use Entangle if you need to.
The easter egg video game
Not funny if you happen to be with a client on April 1st and your working app opens on a silly game that can’t even be closed with Ctrl+Q. (Yes, it happened to me).
The histogram overlay control for exposure and black level 
It’s too easy to inadvertently mess up exposure when cycling through scopes (especially with a Wacom tablet) and it adds unnecessary GUI motion events and redraws. In cases of multiple instances of exposure module, it is automatically linked to the controls of the last instance, which is generally wrong because it is typically masked.
The new filtering option
A beautiful shit made of 6300 lines of bloat and still counting, that needs a screen-reader to understand WTF those icons mean, supposed to fix a problem nobody had with something that adds bugs and trouble. That thing is the poster case of everything that’s wrong in Geektable 4.0. It should be called a regression. The same feature is achieved in Ansel with about 580 lines of code. And to say that the new filtering started as a refactoring project… Never let the darktable idiots refactor anything, it’s too dangerous.
The stars rating  toolbar in lighttable
It’s redundant with overlays and requires to travel too far with the cursor to set it. Use overlays with cursor or key shortcuts to set stars.
The timeline 
terrible code and a huge loss of CPU cycles for a niche feature that essentially serves no purpose. This was responsible for way too many SQL requests and removing it is responsible for most of the GUI responsiveness improvement.
The main window borders with collapsing arrows / silly cycling through headers
The borders marked with arrows allow to collapse or expand the GUI panels. But they waste space, are typically too narrow for many displays, and tend to reappear when you don’t want them because their state is defined per view. Collapsing panels is done with Ctrl + Shift + L(eft), Ctrl + Shift + R(ight), Ctrl + Shift + T(op) for the header, and Ctrl + Shift + F(ilmstrip) for the bottom panel. Shift + F11 toggles all panels at once, F11 toggles fullscreen. And the global menu (you know, like in any app since 1990) now exists and takes care of all that from its Display menu, along with everything else darktable buried inside cryptic icon-buttons.
The silly cycling through all the possible combinations of headers and bottoms that happened when hitting these shortcuts in darktable has been completly removed: each shortcut toggles exactly one panel and nothing else.
Removing the borders allowed to increase the width of the sidebars scrolling sliders for better interaction.
The second darkroom window 
darktable is slow enough with 2 pipelines (thumbnail & preview), a third one is not realistic. This should have been the main preview redirected to another window but the code has been hastily hacked by copy-pasting, it’s terrible. Also there is no traceability on which display profile will be used, good luck with that.
The block and timeout overlay mode in lighttable
terrible code for another niche feature that nobody tests until bug appear on the issue tracker that will be answered with “it works on my computer”.
The extended overlays mode for thumbnails
each of the EXIF metadata display triggered its own SQL request per-thumbnail, because no cache was used, because the guy who coded that doesn’t learn or doesn’t care, but such a loss of CPU cycles is inacceptable.
The non-dynamic culling mode and the zoomable lighttable view
Both were ripped out in 2023 because they were a pile of spaghetti code duplicating what the lighttable already did, in a worse way. Both came back later, done right: culling is now simply the Restrict to selection filter button (no separate view, no static/dynamic nonsense nobody understood), and the zoomable lighttable returned as a proper Columns + Zoom pair, with barycentric auto-panning so faces roughly line up across a series. Turns out the features were fine; darktable’s implementation was the problem.
The dark and icon themes
dark themes trigger all sorts of unwanted visual illusions that make color assessment impossible. Their use is discouraged everywhere on darktable’s doc but they are still there.
The ability to assign keyboard shortcuts to Gtk notebook tabs, as well as switching tabs by mouse scroll.
Just because you can doesn’t mean you should, and capturing mouse scroll on inner tabs messes up with sidebar scrolling (you know, the regular scolling over content that doesn’t fit in the viewport).
The VIM-style shortcuts
I bet you never knew, but if you start typing : in darktable, followed by a command, you can trigger stuff. This feature has never documented and the available features are really limited, but that still listens to all keystrokes to check if it should capture them. In Ansel, you can trigger commands by typing Ctrl+P, and the whole UI is mapped to it, so it’s basically a shortcuts search engine that doubles with a command palette.
The histogram profile
That thing is coded by copy-pasting the display code, instead of writing reusable functions. It wouldn’t be that bad if it wasn’t completely misleading and actually broke the over-exposure alert (because, yes, it’s used there too). Because the histogram is captured at the far end of the pipeline, in display color space, it might be already clipped to display gamut. Say you use Rec2020 space as the histogram profile, because it’s the working space, what you see is RGB clipped to display space then rescaled to Rec2020, which means your clipping peak will not be at the far end of the graph, where you expect it. The result is highly misleading and voids the whole principle of a scope. That’s just a whole pile of crap coded by people who have no idea of what a graphic pipeline is and hack small bits here and there because the concept of “modules” fooled them. They might be modular, but they still apply in sequence in the pipeline, so better check your inputs.
Warning messages in modules
I’m responsible for that stupidity. The warning messages were supposed to tell users they are doing things not really intended by the designer (for example, using 2 different steps of white balance correction) and to ask them to double-check if that’s really what they wanted. That backfired badly because users don’t get the difference between an error and an alert, so even when instructed to use 2 white balances (for example, a custom-corrected raw WB), they would get afraid by the “error” and annoy me with questions. Given that this feature is clearly not helping anybody, and did not trigger the expected behaviour (that is, RTFM), there is no point in keeping it. The option to hide them is removed as well.
Favourite presets button
There was this favourite presets button at the left of the bottom panel in darkroom, and I found nobody who ever used it. In fact, most people who I asked did not ever know it even existed. So it’s gone.
Importing from camera
darktable has a way to mount the camera file system (SD or CF memory cards) through USB, using the library GPhoto2. But the desktop environment is also be able to mount the camera as a local hard drive using PTP and/or MTP protocol, possibly also through Gphoto2. In that case, darktable and the OS may compete for access to the USB media, so you need to unmount it first from the OS to be able to open it from darktable. On Windows, you even need to install custom USB drivers to make it work with GPhoto2, but these drivers will prevent the camera to work with the OS until you completly remove and reset them. So this feature is completely removed, and Ansel loads memory cards as USB media through the OS mounts. To enable this, you may have to install Linux packages such as libmtp, linuxptp, libptp, libgphoto2 and possibly gphoto2. For your desktop environnment, you may install kio-mtp and kio-extras on KDE or gvfs-mtp and gvfs-gphoto2 on Gnome. In any case, you are advised to simply use an SD of CF card reader, it’s cheap and prevents most issues that can arise from udev and cameras connected through USB.

Overall, 5 to 6 SQL requests per thumbnail per “mouse over” event are now spared, due to the features removed (which still lets 3 requests…, aka 2 more than what should be).

Préférences

  • The option to display a mask button in module’s header is removed and the button is always shown,
  • The option to display the scroll bars in lighttable and darkroom is removed, scrollbars will always appear in lighttable and will never appear in darkroom,
  • The option to favour speed at the expense of quality is removed (process downscaled thumbnails), quality is favoured. This will produce previews consistent with the main preview and will prevent much confusion among users, at the expense of speed.
  • The option to expand modules on “enable” event and collapse on “disable” event is removed, collapsed state is independent from enabled state (I was the author of that stupidity and even I grew weary of this).
  • The option to scroll to the expanded module is removed, expanded modules will always trigger a scroll to be fully visible in viewport.
  • The option to open only one module at a time is removed. Modules will never be auto-collapsed when a new module is expanded. You may use Shift + Click on a module header to open this one while collapsing all the others.
  • The option allowing to immediately rename a new instance of a module has been removed and users will always be prompted to rename a new instance right after adding it. This simply encourages sane workflows because everybody adding unnamed instances has always hated themselves shortly after. Be nice to your future self people (no, you will not remember).
  • The option to disable the silly behaviour removing the star rating if you hit 1 star twice has been removed because WTF ? To remove the star rating, hit 0 and be done with it. 1 means 1.
  • The option allowing to compute a downscaled preview pipeline in darkroom is removed, and preview pipelines will always be computed at their correct size. This is a can of worms since neighbourhood filters (local contrast, contrast equalizer, diffuse and sharpen, blur, etc.) are accurate only when zoomed-in at 100%. If you zoom-out at screen size, as to fit the image within the viewport, you already introduce a visual inconsistency that produces misunderstanding among users and lots of false-positive bugs reports. But if you even downscale that, you are really pushing your luck and looking for trouble. You don’t pay for that software, at least buy decent hardware to run it properly.
  • The option to use single click to open images in darkroom from thumbnail has been removed. That’s just not how file managers work and it creates too many opportunities to accidentally open images.

Modules deprecated

All the remaining Lab modules that I have warned against for years are deprecated, namely:

  • Bloom, (replaced by diffuse or sharpen, preset blooming)
  • Raw chromatic aberrations, (replaced by RGB chromatic aberrations)
  • Contrast, lightness, saturation, (replaced by filmic and color balance)
  • Colorize, (replaced by color balance)
  • Color contrast, (replaced by color balance)
  • Color correction, (replaced by color balance)
  • Color mapping, (replaced by color mapping features in exposure and color calibration)
  • Color reconstruction, (replaced by filmic color reconstruction, “high quality reconstruction” method)
  • High-pass, (replaced by diffuse or sharpen, various deblurring presets)
  • Levels, (replaced by filmic, white and black relative exposures settings)
  • Low light, (replaced by color balance)
  • Low-pass, (replaced by blurs)
  • Monochrome, (replaced by color calibration, “grey” tab, and various film-emulation presets)
  • Raw denoise, (replaced by denoise profiled)
  • Shadows and highlights, (replaced by tone equalizer and local contrast)
  • Sharpen, (replaced by diffuse or sharpen, various deblurring presets)
  • Soften, (replaced by diffuse or sharpen, blooming preset)
  • Split-toning, (replaced by color balance)
  • Tone curve, (replaced by tone equalizer, filmic and color balance)
  • Velvia. (replaced by color balance)

The display-referred RGB modules have been deprecated too:

  • Base curve, (replaced by filmic)
  • RGB levels, (replaced by filmic, white and black relative exposures settings)

The scene-referred and display-referred processing workflows have been removed too, the scene-referred workflow is the only one and default. The chromatic adaptation workflows are removed too, the modern workflow will always be used.

One of the most common questions, since the big scene-referred change, was “what modules should I avoid”. Now, you don’t need to ask. Despite what some people say, “deprecated” means the modules can’t be found in UI for new edits, but they are still very much in the program and ready to serve for old edits that use them. Deprecating is just GUI cleaning.

The output color profile module has been removed from the darkroom GUI. It is still applied in the pipeline, so only the GUI widget is hidden, but since the output profile is set either from the display options (for the thumbnails and previews) or in the export module (for file exports), the profile defined in the darkroom module was overwritten anyway, and the duplicated setting confused some users. In the export module, the former “same as image” profile option (that used the options set in the output color profile module) has been replaced by “same as original”, which will reuse the embedded color profile if any or fall back to sRGB otherwise (noticeably for raw files). All in all, this only changes where the output profile is set in the GUI and de-duplicate this setting, it does not affect the pipeline.

What was changed from mainstream darktable

Behaviours

Mouse scroll
The mouse scroll will scroll the content of the container (sidebars) and will not be captured by sliders, unless sliders got clicked over first (or used through keyboard shortcuts). This restores the intuitive and common behaviour of a mouse scroll and protects from unwanted setting changes. See #11 . The preference to decide how mouse scroll should be treated is consequently removed.
“Mouse over” event
In lighttable, the “mouse over” event now does not select images for writing and possibly harmful operation (writing metadata, copying history stack, deleting/moving files, applying styles, rating, labelling, tagging etc.). These “mouse over” events trigger only safe read-only events in the metadata display module.
Modules listening to “mouse over”
Similarly, the modules like tagging, geotagging, etc. that reacted to the “mouse over” event (by updating their content) now only react to hard selection (click or key stroke). This saves many SQL requests to read metadata when moving the mouse in lighttable and improves responsiveness.
Copy all
The “copy all” history stack now copies and pastes white balance too. Meaning it does what it says. That used to be the case, but another hasty hack got that changed for madness 2 years ago.
CSS animations
Animations are basically videos that need to be computed at 30 FPS while Gtk is only single-threaded on CPU, that’s just a stupid loss of CPU cycles.
Filmstrip thumbnails
The thumbnails interaction have been synchronized with the lighttable :
  • Opening a new image will need double-click
  • Copy/pasting editing histories in filmstrip view over arbitrary selections will need a interaction with a knobby interface (mouse over event will be disregarded),
  • The weird selection modes relying on key modifiers are removed. Selection is done with regular single click, as in lighttable.
  • Rating/rejecting on overlays in filmstrip is prevented because the controls are too small to prevent misclicking accidents.
Keyboard shortcuts
The great MIDI input thingy of 2021 broke basic functionality and user expectations : the numeric pad events did not listen to the state of numlock and were always recorded as Home, End, PageDown etc. Also, on AZERTY and BÉPO keyboards, the regular number keys are accessed through Shift. This broke the picture ratings because numbers from the numeric pad were not recorded as numbers, and the regular numbers did nothing. When reconfiguring the rating shortcuts with regular numbers, you would then see things like Shift + & on AZERTY or Shift + " on BÉPO, instead of the expected 1.
Then, to get the numpad numbers to work, you had to manually add them as alternative shortcuts. That’s a backstep of more than 25 years regarding UI, all because the MIDI developer thought it was clever to disregard OS key mapping and handle it internally. This has been fixed in a way that gets the OS-decoded key (including modifiers like Shift and numlock when needed), and then remaps all numpad key strokes to regular key strokes, so the Enter, *, /, Delete and all the numeric keys will be treated equally no matter where they are input, without having to duplicate shortcuts for the numpad. It is crazy that this should be announced as a new feature in 2023 and is another proof that darktable development went south thanks to die-hard geeks.
Triple-click has also been removed from shortcuts because promoting repetitive stress injury by design is totally stupid.
Since then, the whole shortcuts handler — the infamous “Great MIDI turducken” of 2021 — has been rewritten from scratch, in a fifth of the code and a sixth of the complexity. MIDI and gamepad support are gone (2% of users, for a tertiary feature), and in their place the interface is fully navigable from the keyboard without memorizing a single shortcut, with a global action search (Ctrl + P) that finds and triggers any command by name. The full story is in the news.

Vues

The less-used views like Map, Print and Slideshow are hidden by default, but can be re-enabled from the Preferences -> Other views. This prevents GUI bloat since the .so objects of the views are simply not loaded at startup (they are not hidden from the GUI, they completely don’t exist). This has the drawback of deleting user-defined shortcuts if any, for these views. But the issue is Gtk initializes and redraws all GUI widgets, whether they are visible or not, so even hidden and unused views will drain your CPU.

Users who want to preserve their shortcuts for the 3 removed views may edit the ~./config/ansel/anselrc file by adding the following lines before starting the software :

1/views/map/enable=TRUE
2/views/print/enable=TRUE
3/views/slideshow/enable=TRUE

Widgets

Capitals
Modules names, buttons and section labels have their initial letter capitalized programmatically as grammar and typography rules suggests for better visual cues and for consistency with the rest of the world. This does not break translations but may trigger weird behaviours with accented characters. This is a work in progress and not all places have capitals yet. It uses sentence capitalization because the code to do so is 4 lines, while using title capitalization would require tokenization and is far less robust to achieve across a variety of languages.
Export
The “export” module is moved to the left sidebar in lighttable, for consistency with import, collect, etc.
DAM modules removed from darkroom
The metadata, tags and export modules are removed from darkroom, since they are DAM features. Exporting an image cannot be done from the darkroom to prevent running 3 concurrent pipelines, which can produce crashes and loss of data if the available RAM is exceeded (the RAM allocation code was still broken back then, especially on GPU; it has since been rewritten from scratch, so Ansel now knows exactly how much memory it uses and never exceeds the user-defined budget). This also frees some space for the image processing widgets in darkroom.
Modules reorganized
Darktable’s “modules” lumped two different things behind the same look: image-processing filters (which live in the pipeline) and arbitrary toolboxes (which are just panels of buttons). The toolboxes have been renamed to plain functional names and sorted by where they belong.
In the lighttable, a single left sidebar holds the file and metadata tools — “Library” (the old “collect”/“collections”), the metadata editor, tagging, “Datetime and GPS” (geotagging) and image information. The whole right sidebar of the lighttable has been removed: once the toolboxes-that-are-really-menus moved out, there was nothing worth keeping there, and the freed space went to the thumbnails.
In the darkroom, the right sidebar is reserved for the image-processing modules, and the left sidebar holds the editing helpers (scopes, snapshots, history of changes, duplicates, mask manager…).
Toolboxes moved to the global menu
The “modules” that took no user input and only displayed buttons — selection helpers, image actions, history copy/paste, styles management, the maintenance scripts — have been moved into the global menu, where hierarchical lists of buttons have belonged since graphic designers invented drop-down menues in the 1980’s. Another thing darktable failed at, for years, while shipping grids of cryptic icons instead.

Presets

Exposure module
The exposure boost has been changed from +0.5 to +0.7 EV,
Filmic
In filmic module, the contrast is changed to 1, latitude is set to 0.01% (which practically disables it — doesn’t matter for v6), and the interpolation spline is set to back to “hard” (fourth order polynomial with $C^2$ connectivity condition).
Color balance RGB
This module is now enabled by default with the “standard colorfulness” preset, as to give a base rendition closer to the infamous out-of-camera JPEG.
Lens correction
This module is now enabled by default because I couldn’t think of a photographer not wanting to correct lenses.
Dithering
This module is now enabled by default because it does no harm but protects JPG and other low-bit-depth exports from posterization.