" Introducing the darktable Uniform Color Space 2022
The darktable UCS 22 is a perceptually uniform color space designed
from psychoperceptual experimental data specifically for the purpose
of artistic saturation changes, as performed in the *color balance RGB*
module.
It uses a brightness-saturation scheme that compensates for the
Helmholtz-Kohlraush effect
(accounting for the contribution of colorfulness in perceived brightness)
and allows an efficient gamut-mapping against pipeline RGB at constant
brightness. It will make the saturation control in *color balance RGB*
better behaved."
I have looked for this UCS 22 colour space in the input color profile
module and I tried to find information in the latest user guide, but I
don't see it anywhere. Is this just something that is hidden from the user
or is it something I should be selecting somewhere.
Thanks
Terry
On Sun, 3 Jul 2022 at 03:05, Pascal Obry <pas...@obry.net> wrote:
>
> We're proud to announce the new feature release of darktable, 4.0.0!
>
> The github release is here: [
> https://github.com/darktable-org/darktable/releases/tag/release-4.0.0](https://github.com/darktable-org/darktable/releases/tag/release-4.0.0)
> .
>
> As always, please don't use the autogenerated tarball provided by
> github, but only our tar.xz file. The checksums are:
>
> ```
> $ sha256sum darktable-4.0.0.tar.xz
> 1416f8f59717e65a6220541aaa12eacca93888ce5176f2c9ab6c17b9cc53cc2d
> darktable-4.0.0.tar.xz
> $ sha256sum darktable-4.0.0.dmg
> addab784af18bafa303340e754c00084c126e61c3d5b93006f8e6d602f838203
> darktable-4.0.0.dmg
> $ sha256sum darktable-4.0.0-win64.exe
> d0e09efb2f74beae9f5387a296d366c160d9fb87e571c9559c53cd0111b7b955
> darktable-4.0.0-win64.exe
> ```
>
> When updating from the stable 3.8.x series, please bear in
> mind that your edits will be preserved during this process, but the new
> library and configuration will no longer be usable with 3.8.x.
>
> You are strongly advised to take a backup first.
>
> #### Important note: to make sure that darktable can keep on supporting
> the raw file format for your camera, *please* read [this post](
> https://discuss.pixls.us/t/raw-samples-wanted/5420?u=lebedevri) on
> how/what raw samples you can contribute to ensure that we have the *full*
> raw sample set for your camera under CC0 license!
>
> Since darktable 3.8:
>
> - Almost 1600 commits to darktable+rawspeed
> - 586 pull requests handled
> - 123 issues closed
>
> ## The Big Ones
>
> The following is a summary of the main features added to darktable 4.0.
> These features
> are described more fully in the user manual and accompanying blog post.
>
> - Color and exposure mapping
>
> A new feature in the "exposure" and "color calibration" modules allows
> you to
> define and save a target color/exposure for the color pickers, in order
> to
> match any source object in the image against an arbitrary target
> color. This can be used to perform white balance
> (chromatic adaptation) against non-gray objects of known color, or to
> ensure the color consistency of an object across a series of images.
>
> - Filmic v6
>
> Filmic v6 introduces new color science. This change removes the
> mandatory desaturation
> close to medium white and black and replaces it with a true gamut
> mapping against the output (or export) color space. This allows for more
> saturated colors, notably in blue skies.
>
> For users who still prefer the "desaturated highlights" look,
> you can still do this by disabling chroma preservation, but v6 adds a
> hue handcuff to prevent the traditional hue shift that comes with this
> method (where saturated blue skies degrade to cyan and saturated red to
> yellow).
>
> This gamut sanitization is the third and last to be added to darktable,
> which now has a fully-sanitized color pipeline from input (color
> calibration),
> through artistic changes (color balance rgb) to output (filmic v6). Users
> can now color-grade pictures safely in the knowledge that invalid input
> colors can be recovered in the least destructive fashion possible early
> in the pipeline, and valid colors can't be pushed out of gamut along the
> pipeline.
>
> Note: If modules are applied after filmic in the pipeline, they
> don't benefit from this gamut mapping and rely on LittleCMS2 (if
> enabled) at the final export stage, which does not gamut map as it
> should, and probably never did.
>
> - Guided laplacian highlight reconstruction
>
> A new "guided laplacian" method has been added to the "highlight
> reconstruction" module. This uses an iterative and multi-scale wavelet
> scheme to extract valid details from non-clipped RGB channel(s) if any,
> uses these details to guide the reconstruction of clipped channels, and
> finally
> propagates the color gradients from neighboring valid regions using
> edge-aware color diffusion. This limits color bleeding through edges
> (preventing green leaves from bleeding color in the reconstruction of
> clipped
> blue sky, for example).
>
> A noise setting allows Poisson noise to be added to reconstructed
> highlights,
> in order to help blend them into noisy high-ISO images.
>
> This method is only available for Bayer sensors and cannot be adapted
> to X-Trans sensors.
>
> - Introducing the darktable Uniform Color Space 2022
>
> The darktable UCS 22 is a perceptually uniform color space designed
> from psychoperceptual experimental data specifically for the purpose
> of artistic saturation changes, as performed in the *color balance RGB*
> module.
> It uses a brightness-saturation scheme that compensates for the
> Helmholtz-Kohlraush effect
> (accounting for the contribution of colorfulness in perceived brightness)
> and allows an efficient gamut-mapping against pipeline RGB at constant
> brightness. It will make the saturation control in *color balance RGB*
> better behaved.
>
> - UI Rewrite
>
> The UI has been completely revamped again to improve look and
> consistency.
> Padding, margins, color, contrast, alignment, and icons have been
> reworked
> throughout.
>
> Collapsible sections within modules have also been redesigned so that
> their functionality is more obvious and better-looking.
> New collapsible sections have been added to avoid
> cluttering the UI in the following modules:
>
> - channel mixer rgb
> - exposure
> - color calibration
>
> The vignetting module has been split into two sections for clarity.
>
> Superfluous sections have been removed from the "crop" and "white
> balance".
>
> Support has been added for the IPAPGothic font.
>
> The module-description tooltips have been reworked to ensure better
> layout.
>
> Finally the default theme has been changed to Elegant Grey. The
> darktable default is now in line with the theme recommended by the
> team.
>
> - Performance and OpenCL support changes
>
> All performance and OpenCL settings and pixelpipe optimizations have been
> fully reviewed and updated. Many new optimizations have been
> added and the user preferences have been simplified.
>
> All configurations are now per-device allowing each OpenCL
> device to be tuned separately.
>
> Performance configuration is now applied at runtime and no longer
> requires darktable to be restarted when changed.
>
> Some modules had incorrect or overly conservative tiling factors, which
> made
> darktable unnecessarily slow (since tiling was used when it was not
> required)
> The followimg modules have been updated
>
> - demosaic (X-Trans)
> - retouch
>
> ## Other Changes
>
> - Color glossary
>
> The global color picker tool (in the darkroom's left sidebar) now
> displays
> the name of the picked color in the tooltip. This feature was
> requested by several color-disabled photographers, to assert the
> perceptual validity of their editing for an average observer.
>
> The color vocabulary contains 76 entries: 15 hues × 5 lightnesses +
> neutral (gray). It does not separate across the chroma axis, so all
> colors are registered the same no matter their colorfulness.
>
> The vocabulary also contains average skin colors for 3 body
> parts (forearm, forehead and cheek) of 6 ethnicities (Chinese, Thai,
> Kurdish, Mexican, Caucasian, African-American). These values come from
> the academic databases of cosmetology and dermatology available at the
> time of programming. They are only valid for a D65 illuminant and for
> an exposure setting that anchors diffuse white at 92% relative
> luminance.
>
> - A new "contrast" parameter has been added to the guide line overlay
> settings, allowing for better visibility of the lines over images.
>
> - A new "collection filters" module has been introduced, designed to be
> easier
> to use than the filtering in the current "collections" module.
>
> The new module allows the current collection to be sorted and filtered
> using multiple
> criteria. Each sort/filter rule can be pinned, which duplicates the
> appropriate control
> on the top tool bar for quick access.
>
> The following filters have been implemented (more to come in the next
> version):
> color labels, text search, date-time filters, exposure, ISO,
> focal length, aperture, aspect ratio, filename and extension,
> grouping, history, local copy, module order
>
> Presets can be created and a history button also allows previous
> configuration to be retrieved.
>
> All-new text and color filter widgets have been implemented.
>
> - The "recently used collections" module is now incorporated into the
> "collections" module as a "history" button
>
> - The darkroom's module search facility has been enhanced to also match on
> any user-defined module names.
>
> - Support for EXR 16-bit (half) float export has been added.
>
> - All usage of dates/times have been reworked to better support
> time-zones and differing operating systems. Support for
> milliseconds has also been added.
>
> - All presets in the "tone equalizer" module have been updated to use
> scene-referred blending modes.
>
> - The new input system introduced in version 3.8 now handles
> simultaneous shortcut presses and the responsiveness is
> greatly improved.
>
> MIDI configuration parameters are now specified in darktable
> resource files.
>
> Slider step sizes have been standardized and can now be
> configured individually.
>
> Extra pen tablet button clicks are now treated as key presses so that
> they can be used in shortcuts.
>
> Support for gamepad triggers has been added (treating them as buttons)
> allowing them to be used as shortcuts.
>
> - Modifiers (<kbd>Ctrl</kbd>/<kbd>Shift</kbd>/<kbd>Ctrl+Shift</kbd>)
> can now be used when dragging sliders, to modify the precision of the
> value changes.
>
> - When using the "copy" and "move" functionality in the lighttable, the
> last
> directories are remembered independently for each operation.
>
> - It is now possible to scroll over a tabbed module to switch tabs.
>
> - Improved monochrome images support:
>
> True monochrome images (like those from Leica) and images from cameras
> that have the color matrix filter in front of the sensor removed,
> are now treated the same in the user interface as much as possible.
>
> - The tagging suggestion mode has been improved.
>
> - The overlay layout in the print view has been enhanced.
>
> - The "retouch" module's heal iteration limit has been increased for new
> edits.
>
> - It is now possible to edit a single node on a brush path. You can
> change the size, opacity and hardness of each node independently.
>
> - A new button in the "highlight reconstruction" module allows clipped
> pixels
> to be better visualized.
>
> - The raw overexposure function now shows actual sensor clipping rather
> than being
> adjusted according to the white balance of the image. This is better
> suited to the default scene-referred workflow.
>
> - Shortcuts can now be directed to the currently-focused processing module
> instance instead of the currently-expanded one.
>
> - The control of the lighttable view has been improved by ensuring the
> up/down
> and left/right keys have the expected behavior.
>
> - Apply a blur when color picking in area mode. This ensures that color
> picker
> measurements aren't overly influenced by image noise. This change
> particularly
> improves the stability of filmic's black relative exposure measurement.
>
> - Add support for DNG GainMap EXIF information and update the pixel
> gain in raw-prepare module. This gives a better initial exposure
> to the imported DNG pictures.
>
> ## Bug Fixes
>
> - Check for total memory on Linux is now more portable.
>
> - MIDI buttons with light status are now properly updated.
>
> - Tab shortcut tooltips are correctly displayed on tabbed modules.
>
> - Misalignments between source and target patches in the retouch module
> have been resolved. "Jumpy" movements are also improved when adjusting
> nodes or segments.
>
> - The start of culling mode is improved, especially where no images are
> selected and/or under the mouse.
>
> - Local-copy status icon position fixed in block overlay.
>
> - Crop handle positions fixed when using fast movements.
>
> - RCD OpenCL tiling issues resolved.
>
> - Tile stitching for X-Trans sensors
>
> - Filmstrip update fixed if crop is left open when moving to next
> image.
>
> - "collections" module now correctly updated when new images are imported.
>
> - Landscape/portrait print handling was broken due to a recent CUPS
> change. We
> now rely on the CUPS filter for the proper orientation.
>
> - Fixed possible PDF corruption in export and print modules due to
> duplicate written byte count.
>
> - Fixed a possible race conditions in retouch and color reconstruction
> OpenCL code making darktable crash.
>
> - Properly transform points for the rotation computation in
> perspective correction. This fixes an issue when the image is
> flipped making it impossible to use the rotation control.
>
> - Removed RatingPercent in EXIF data as it is not standardized and
> can confuse the Windows image viewer.
>
> - Fixed label/reject behavior when multiple images are selected:
>
> When attempting to reject multiple images, they will now be set to
> rejected if
> **any** of them are not currently rejected. They will be set to
> un-rejected if
> **all** of them are currently rejected.
>
> This allows for more predictable handling of images with inconsistent
> reject statuses.
>
> Similar changes have also been made when toggling color labels on/off.
>
> - Fixed white balance preset lookup in the "white balance" module.
>
> - Fixed some possible missing refresh of the metadata editor.
>
> - Fixed possible translation issue on Windows.
>
> ## Lua
>
> ## Notes
>
>
> ## Changed Dependencies
>
> N/A
>
> ## RawSpeed changes
>
>
> ## Camera support, compared to 3.8
>
> ### Base Support
>
>
> ### White Balance Presets
>
> - Nikon D4S
> - Panasonic DC-S5
> - Sony ILCE-7M4
>
> ### Noise Profiles
>
>
> ### Custom Color Matrices
>
> ### Suspended Support
>
> No samples on raw.pixls.us
>
> - Canon EOS M2
> - Creo/Leaf Aptus 22(LF3779)/Hasselblad H1
> - Fujifilm FinePix HS50EXR
> - Fujifilm FinePix S6000fd
> - Fujifilm FinePix S9600fd
> - Fujifilm IS-1
> - GoPro FUSION
> - Kodak EasyShare Z980
> - Leaf Aptus-II 5(LI300059)/Mamiya 645 AFD
> - Leaf Credo 60
> - Leaf Credo 80
> - Leica D-LUX 6
> - Minolta DiMAGE 5
> - Nikon 1 J4
> - Nikon 1 S1
> - Nikon Coolpix P7700
> - Nikon D1H
> - Nikon D2H
> - Nikon D3S
> - Olympus E-10
> - Olympus SP320
> - Olympus SP570UZ
> - Panasonic DMC-FX150
> - Panasonic DMC-G2
> - Pentax K200D
> - Pentax K2000
> - Pentax Q10
> - Phase One IQ250
> - Samsung GX10
> - Samsung GX20
> - Samsung NX5
> - Samsung NX10
> - Samsung NX11
> - Samsung NX20
> - Samsung NX2000
> - Samsung EK-GN120
> - Samsung SM-G920F
> - Samsung SM-G935F
> - Sinar Hy6/ Sinarback eXact
> - Sony DSLR-A380
> - Sony DSLR-A560
> - ST Micro STV680
>
> ## Translations
>
> - Czech
> - German
> - Esperanto
> - European Spanish
> - Finnish
> - French
> - Hebrew
> - Hungarian
> - Italian
> - Japanese
> - Dutch
> - Brazilian Portuguese
> - Russian
> - Slovenian
> - Turkish
> - Ukrainian
> - Chinese - China
>
> --
> Pascal Obry / Magny Les Hameaux (78)
>
> The best way to travel is by means of imagination
>
> http://www.obry.net
>
> gpg --keyserver keys.gnupg.net --recv-key F949BD3B
>
> ____________________________________________________________________________
> darktable user mailing list
> to unsubscribe send a mail to
> darktable-user+unsubscr...@lists.darktable.org
>
>
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