Scene-Referred Workflow

January 27, 2026

Scene-Referred Workflow is the heart of modern darktable software and distinguishes it from programs like Lightroom or even older darktable versions.

1. The Basic Problem: Display-Referred (The Old Way)

In the past (and in many other programs), the image was forced into the screen’s color space (usually sRGB or AdobeRGB) very early in the processing chain (pixelpipe).

  • The Problem: Camera sensors have a huge dynamic range (very bright to very dark). Screens have a small one.
  • If you “compress” the image to the screen’s range too early (tone mapping), you lose the physical relationship to light. Bright highlights (sun, lamps) are simply cut off (clipped) at “white” (value 1.0 or 255).
  • Operations like “increase exposure” or “blur” then often look artificial because the real light information is missing.

2. The Solution: Scene-Referred (The New Way)

In the scene-referred workflow, darktable treats pixel values as physical light values for as long as possible.

  • Unlimited Space: There is no upper limit at “white”. A pixel can have the value 1.0 (white), but also 10.0 or 100.0 (much brighter than white, e.g., the sun).
  • Physics: Modules like Exposure, Color Calibration, or AgX work linearly. This means if you double the exposure, the numerical value simply doubles. This corresponds exactly to what happens when you make the light brighter in reality.
  • Late Tone Mapping: Only at the very end of the pixelpipe is the image “translated” for your monitor. This is done by modules like AgX. They take this huge dynamic range and elegantly compress it into the range your monitor can display.

Why is this important for you?

  1. HDR Handling: You can rescue highlights that would have simply burned out in the old workflow because the information “brighter than white” is preserved until AgX makes it visible again.
  2. More Natural Colors: Since colors are mixed physically correctly, there are fewer strange color shifts (e.g., a blue sky doesn’t suddenly turn gray or purple when darkened).
  3. Module Order: In darktable, the order is fixed (from bottom to top).
    • Bottom (Raw): Physical corrections (Exposure, White Balance).
    • Middle: Creative adjustments.
    • Top: Tone Mapping (transformation to the screen) (AgX).

Important: Some modules like Watermark or Grain are display-referred and are applied after tone mapping. However, they have no influence on image quality.

Quick Guide for the Workflow

When you open a RAW image, darktable automatically does the following in modern scene-referred mode:

  1. Exposure: Raises the brightness so that the midtones (the main subject) are correctly exposed. Highlights are allowed to burn out (have values over 1.0).
  2. Color Calibration: Takes care of white balance (CAT).
  3. AgX: This is the “compressor”. It brings back the blown-out highlights (values > 1.0) and ensures that the black is crisp.

Your Job:
You only adjust the brightness of your main subject in the Exposure module. Ignore if the sky burns out. You fix that afterwards in the AgX (Tone Mapping) module.

In summary: Scene-Referred simulates real light until the very last moment, while Display-Referred pretends the image is already a finished photo on the monitor.

You can find more information in the official manual: scene-referred workflow
Questions about this topic? Discuss with us in the forum!

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