tone mapping

Camera sensors are capable of capturing a wider dynamic range than can be displayed on a monitor or print. So at some point during processing the cameras data has to be compressed or clipping will occur. This is called tone mapping or sometimes a display transform. You may be familiar with the term tone mapping from HDR-processing but it is not limited to that field: every JPEG produced by your camera and every raw processing application has to tone-map at some point. In many other raw-processors, the tone mapping is done early in the processing pipeline. In darktable’s scene referred approach it is usually one of the last modules in the module order.

Typically exactly one tone mapper is enabled for an image, but darktable allows you to be creative and have zero, one, or more tone mappers enabled. For instance, scenes with a low dynamic range can work well without any tone mapper.

darktable has four scene-referred tone mappers:

• AgX
• filmic rgb
• sigmoid
• spektrafilm

In the display-referred workflow, which darktable offered as a default in the past, base curve is used early in the pipeline.

You can enable a default tone mapper in preferences > processing > auto-apply pixel workflow defaults.