I've been using @patdavid's film emulation pack for a while, and as a darktable user I've always found the round-trip between darktable, GIMP and G'MIC to be rather lengthy (compared to Rawtherapee and others developers that fully integrate the process into the pipeline). So with the recent discussion of LUTs and despite the introduction of the "color checker lut" module in darktable, I still decided to implement a Hald CLUT module. This way I can see the final effect in live action.
Here is what it looks like right now:
's Fuji Superia 400 emulation on the left)
Some things of note:
- It basically takes a path to the LUT and applies that, you can tweak the strength of the effect with darktable's blending modes.
- It only supports LUTs in PNG format currently.
- The LUT is applied very late in the pipeline (after output color profile).
- Currently it only stores the file path but not the actual LUT in the sidecar, so sharing the sidecar across users can be problematic.
I will clean up the code and post the source later in case someone wants to play with it.