These options control some of the internals processing of darktable.
If this option is activated, darktable will use system library LittleCMS 2 instead of its own routines. This is significantly slower than the default but might give more accurate results in some cases (default off).
Note that if the given ICC is LUT-based or contains both, a LUT and a matrix, darktable will use LittleCMS 2 to render the colors regardless of this configuration parameter's value.
Pixel interpolator used in rotation, lens correction, up-and-down scaling; options are “bilinear”, “bicubic”, “lanczos2”, “lanczos3” (default).
Set folder that contains Lut files used by lut 3D module. (need a restart)
With that setting, you can define which default workflow to work on. Two workflows are available:
Scene-referred workflow is based on linear modules and will auto-apply filmic and exposure. This workflow consist of adding, by default, +0,5 EV of exposure (in exposure module), to adjust the global brightness and mid-grey to a similar value to that used by most JPEGs produced by SLR cameras. The interest of filmic is to apply a tone mapping curve at the end of the pipeline, allowing a physically realistic retouching on RGB values encoded linearly before, but also to manage color consistency through the tone mapping, in order to preserve hues as much as possible and to avoid gamut overruns.
This default +0,5 EV value can be overridden using an auto-apply preset if it is found the images from a particular camera are consistently too dark.
The scene-referred workflow also enables by default the "compensate camera exposure" option in the exposure module, to adjust the global brightness appropriately in cases where the camera's exposure compensation dial was used to protect highlights in the image or Expose To The Right (ETTR) to optimally make use of the sensor's dynamic range.
Display-referred workflow, used by default, is based on Lab modules and will auto-apply base curve and the legacy module pipe order (darktable 2.6 and older). It will apply the non-linear transformation at the beginning of the pipeline, and all editing will then be done on non-linear RGB.
A third option is available to not use any workflow and so deactivate all automatic modules. That allow you to manage your pipeline manually.
Use the per-camera basecurve by default instead of the generic manufacturer one if there is one available. For more details see Section 184.108.40.206, “Base curve” (default off).
This added sharpen is not recommended on cameras without a low-pass filter. The default is to not add any sharpening automatically as most recent cameras have no low-pass filter. (need a restart)
If switched on, darktable analyses the preview image available via exif data during import or refreshing exif for being monochrome and sets the darktable|mode|monochrome tag accordingly. As this reduces performance it is turned off by default. Turn on for better monochrome image workflow support.