"Scene-Referred Default" preset in Filmic RGB

[Neutral_Gray]

For a moment, I thought that the current “half-solution” couldn’t be fixed because Aurélien was the driving force behind Filmic RGB. So when I saw that it was already four years after the “TODO” had been marked in the code notes, I thought it was because he had abandoned Darktable.

Instead, the “problem” - or rather my naïveté - goes deeper.

1. My points were already brought up in a pixls thread four years ago:

@garrett

It does seem like filmic probably should automatically adapt to exposure’s setting. I suppose this might be an oversight?

2. The answer was that such a connection between modules would be impossible by design:

@anon41087856

Darktable’s pipeline is designed such that modules don’t care about each other, so filmic cannot get the exposure value from the exposure module and just assumes a flat +0.5 EV. It’s a core design problem that doesn’t have a simple solution for now (except redesigning the pipeline… again).

As a workaround, one user proposed using presets, even detailing the calculation:

@Matt_Maguire

Fortunately, you can deal with this using presets.

But with presets, you either accept having only a small number of values in Exposure that you could choose with this method, or you would need very many presets, the more precise you’d want it to be (e.g. using +1.11EV instead of +1EV).

Question: Is it technically feasible to use a Lua Script to “grab” the current exposure value from the history stack, apply a simple calculation (the current default one, but based on effective exposure) before inserting the values into Filmic’s relative black/white exposure?
This would replace the current 0.7EV dummy value.

I have read numerous reasons why this should not be possible. Still, as one user said, it would provide a starting point:

@alpinist

I know that filmic is not supposed to be automatic, but for sure it would be possible to create an auto mode for filmic that better matches expectations for a default usable result. Filmic would stilll allow the same artistic expression, but it would be easier to process huge batches of boring pictures.