Darktable: Fun with LUTs
darktable lut plot visualizationDarktable added a lut3d module a while ago. The module supports loading and
applying 3D LUTs (Look Up Tables) that come as Cube or Haldclut files.
Apparently LUTs are quite commonly used in the film industry, which means there are quite a few sites out there where people share their LUTs. For example https://freshluts.com More resources are linked from the Darktable blog post on lut3d.
The great thing about LUTs is that they allow you to quickly apply a style to images similarly to Instagram filters. So they are quite fun to play with.
Same image with different LUTs applied.
When I was looking for tools to convert LUT formats, I came across
ColorPipe-tool
and PlotThatLUT, which provide a nice way of visualizing the
mapping that a LUT defines. Unfortunately the code is not maintained and does
not work with Python3 or recent verions of PyOpenColorIO. So I spent a few minutes fixing it up (http://github.com/sgtm/ColorPipe-tools) and now you can easily get nice plots from LUTs:
The bleak LUT from above. Notice the compressed color space
A different LUT which maps to more of the color space