Luts: scene vs display

Software darktable
1

DT 3.8.1

I have b&w 3dlut that I really like, but looking at the module, it shows that 3dluts are display referred.

I’ve been mostly using scene referred as recommended. I have tried to replicate the lut with the color calibration > gray, but I can’t get it as nice.

  1. Where is the lut in the scene referred pipeline?
  2. It looks like it’s after filmic, from the 2nd tab. But is it how it’s going to be processed?
  3. If the lut is, in the pipeline, after the filmic, what are the implications?

Thanks

2

LUT is after filmic, in display referred part of the pipeline. This means you’ll be working in the display referred space. It should be fine, since so many LUTs are meant to be applied in display referred space. As long as the LUT doesn’t push the values too hard, it should be fine.

3

If your lut contains a curve - that is contrast/tonal changes, then you can either disable filmic and just use the lut instead, or you can enable filmic and use the white/Black relative sliders as usual, but apply no contrast, so instead of an s curve in filmic you just have a straight line.

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4

I suspect many images that get luts applied, well depending on the lut of course will not actually even need filmic. Personally I have been working on a workflow (early days) that uses neither filmic or the base curve… I start by using the auto exposure setting and then I use 2-3 instances of the tone eq. I am finding in early experiments that I can manage highlight detail better… If things are blown it remains to be seen where this takes me…could be a fad but I have had some good success and no messing with color preservation norms and the like… still lots of room to work on color with CB and CC instances…

5

Very interesting. I’ve been playing with that, it’s different but interesting. I’ll have to try on more contrasty photos.

Thanks

6

I just tried it and the b&w image is fairly flat and would like more contrast.

Then where should I apply/create the contrast?

Thanks

7

Tone equaliser

8

A lut that normally is meant to be used on an image that is pretty much already ‘done’, means it goes after filmic (so above it in the list of active modules :wink:). This is also the default order now IIRC .

I have a (hald) lut i sometimes use, that has a subtle warming / saturation effect. I apply it after filmic and any other modules (so basically just before the output module ).

Luts that are meant to be used on more linear data, can be used before . But those luts are rare, and will destroy any data over 1.0 generally speaking. (So exposure can’t be too high before applying the lut. After the lut is applied it can be raised more if you want ).

9

the default module order (lut after filmic) is ok. Originally it was the other way round but I fixed it (i.e. the other devs accepted and merged my fix). So for most luts, it’s after.
Edit: wait, has someone changed the module order again?

10

Nope, just checked on the latest master (3.9.0+1434) and lut comes right after filmic. Which is also the case for 3.8.0/1

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