Zasoby

Color theory readings

What resources can be found online and in libraries to help understand some color theory ?

Common misconceptions

This page addresses most of the mistakes and misconceptions about Ansel that can be found online.

Matematyka modułu diffuse or sharpen

Ten artykuł dokumentuje matematykę aktualnie zaimplementowaną w module diffuse or sharpen Ansela, w postaci, w jakiej występuje w plikach src/iop/diffuse.c, src/common/bspline.h, data/kernels/diffuse.cl oraz data/kernels/bspline.cl. Nie jest to poradnik użytkowania. To rekonstrukcja modelu numerycznego na podstawie kodu źródłowego, w której twierdzenia naukowe zostały prześledzone aż do odwołań cytowanych w komentarzach kodu.1

The mathematics of guided laplacians and harmonic transposition

This article presents the mathematics of Ansel’s highlight reconstruction : the original 2021 guided laplacians design, whose general ideas had only ever been sketched on the pixls.us forum,1 and harmonic transposition, the method that replaced it after a ground-truth study exposed a magnitude-recovery bug.2 It is organized so each reader finds their section : the results and each method’s Intuition & background need no mathematics ; developers will find the Implementation & optimizations subsections and the performance study ; the theoretical findings and the graveyard annex are written to be reusable outside photography ; and how this work was actually done documents the man–machine research protocol behind it.

Zarządzanie kolorami dla użytkowników Linuksa

Linux wciąż ogromnie pozostaje w tyle za MacOS-em, a nawet za Windowsem, jeśli chodzi o zapewnienie spójności kolorów wyświetlanych na monitorze. Powszechnie wymuszane przyjęcie serwera graficznego Wayland w większości dystrybucji Linuksa jeszcze bardziej pogorszyło ten stan, ponieważ zarządzanie kolorami było przez długi czas odrzucane przez twórców Waylanda. Specyfikacja CMS w Waylandzie została ostatecznie naszkicowana w 2020 roku, a kod scalono z główną gałęzią Waylanda w 2025 roku, przez zewnętrznych współtwórców, po długiej walce twórców wcześniejszego oprogramowania CMS z historycznymi twórcami Waylanda.1 Od tego czasu stan obsługi CMS jest bardzo niejednoznaczny w różnych środowiskach graficznych i dystrybucjach. A mimo to wstępne wyniki telemetrii Ansela pokazują 67 % przyjęcia Waylanda wśród użytkowników Ansela.

Supported cameras and formats

This page lists all the known cameras and whether or not their raw files are decoded by Ansel, as well as all file types supported in input and output.

Cameras

Wprowadzenie

Some cameras may use different encoding formats (12 bits, 14 bits, sRAW, compressed or not) and image ratios (4:3, 16:9, 3:2). Because one or more of these formats is supported doesn’t imply they all are. Different cameras may share the same sensor and electronics, even though their commercial name is different: those will be found in the aliases columns.

White balance(s)

We all know what “white” is. We can picture a white sheet of paper. We know it is white because we learned it. But if you put your paper sheet under a summer sun, or a cloudy sky, or at home with those warm living-room bulbs, that white will change color. It might disturb you for the first few seconds, then you will just forget about it: your brain will adapt. But adapt (to) what ?

Troubleshooting color issues

This will apply to upstream Darktable as to Ansel since they share most of their color pipeline. The following procedure will help you troubleshoot your color issues, whether it is inconsistent appearance between export vs. preview, or between screen vs. print, or between 2 apps.

Setup your desktop properly

The inherent problem of color is it exists only as a perception, and that perception is highly contextual and fluid. If I take any color patch and display it over a white, middle-grey or black background, it will not appear the same even though a colorimeter would confirm it’s the exact same color. I have built a little web animation to showcase this effect, displaying sRGB gamut slices at constant hue, over user-defined background lightness : the sRGB book of color .

Color lexicon

mindmap
  root((COLOR))
    color appearance model
      uniform color space
        chromaticity
          U, V
          a, b
        lightness
          L
        delta E
      chromatic adaptation transform
        illuminant
          color reproduction index
          color temperature
      surround lighting
      background lightness
    dimensions
      Munsell
        hue
        chroma
        value
      natural color system
        blackness
        saturation
        hue
      CIE
        lightness
        brightness
        saturation
        chroma
        colorfulness
        hue
    measure
      colorimetry
        tristimulus
          sensor
            Luther-Ives criterion
            metamerism
            dynamic range
            noise
            mosaicing
              Bayer
              XTrans
              zipper artifacts
          spaces
            rgb(RGB)
              HSV
              HSL
            LMS
              Yrg
            XYZ
              Yxy
                Yuv
                  Ych
            CYM
              CYMK
            primaries
              cone cells
              LED
                ITU BT.Rec 709
                ITU BT.Rec 2020
                DCI P3
              inks
      spectrometry
        light spectrum
          wavelengths
          energy
      photometry
        luminance
    correction
      profile
        matrix
        lookup table
        transfert function
      color grading
        ASC CDL
        channel mixer
        curves
      white balance

Translated from English by : Claude. In case of conflict, inconsistency or error, the English version shall prevail.
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