loog is my personal workflow for digitaly developing film negatives.
"loog-dev" is a gizmo(plugin) which allow to use that workflow in Foundry Nuke software.
This is a usual nuke node with no dependencies, you can just copy the content of loog-developer.nk and paste it in a Nuke scene.
Loog works with camera raw file as input. This is because we need to ensure no color-transformation is applied on the data captured by the camera. (loog could also work on non-raw file but might produce less consistent result)
Workflow is described as :
- debayer camera raw file to an untransformed linear encoding
- remove base film layer by sampling the negative
- white balance the image to adjust color rendition
- invert the negative by converting density to transmittance
- apply a 1D "S-shaped" curve transform with user-control to adjust intended exposure
An optional step include applying the camera color matrix just before 5. but it has not be proved to produce visually pleasing result.
Even if there is no colorspace transformation along the process, the output is assumed to be sRGB and work nicely as such.
This workflow offer creative color during 3. and 5., where 3. allow you to adjust the color feel of your picture (ex: warmer, colder) while 5. adjust the contrast and the brightness perception.
- The 1D curve is a node made by Jed Smith: https://github.com/jedypod/nuke-colortools/blob/master/toolsets/transfer_function/Tonemap_PiecewisePower.nk which is itself based on a formula by John Hable.