Applying LUTs and recovering highlights

Hi!

Just a question. Is applying a LUT in darktable a destructive action? I’m trying to recover some highlights after I apply a high contrast LUT to an image with not much success. I come from Lightroom and I am able to restore the highlights successfully there using its Highlights slider. What is the preferred module to do the same in darktable? I see that there are “highlights reconstruction”, “highlights and shadows” and “tone curve” modules, but I’m not getting satisfactory results with any of them.

Any ideas?

Thanks

Can you post the raw image and the LUT?
There are multiple ways to go about it. Is your workflow display referred or scene referred?

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What’s your intention of applying a LUT? Do you want to correct a flat profile applied to a jpeg? Or do you want to change the look for a processed image?
If it’s the latter then the LUT Module is better moved above filmicrgb and all further modules dealing with colors in the right tab of used modules (ctrl+shift drag).

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It’s a classic film emulation LUT. My intention is to change the look of the image.

Here is a ZIP with both the LUT and the raw file.

highlight-recovery.zip (16.1 MB)

So, I need to reorder the LUT module?

The LUT seems to raise the Blacks. If the LUT is applied before filmic, filmic tries to stretch it again over the whole tonal range. so it’s better used after filmic (above filmic module in the right module list).

I’ve put the LUT module after Filmic, so the LUT effect is not affected by the Filmic processing. But, my question was, how can I recover some of the highlights (I don’t need all the details, just some of them) AFTER applying the LUT?

I just dropped exposure, can you post your lightroom result so I can recreate in Darktable?

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As you can see, I just want to recover just a bit of detail in the shirt, I don’t need to recover all the details.

Nailed it! :slight_smile:


test.ORF.xmp (41.9 KB)

Edit: Ah, I’ve messed up the grain :crazy_face:

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First set highlight reconstruction mode to „Reconstruct in LCh“
Further it might be a task for the new highlight reconstruction tab in filmicrgb v4.

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There :slight_smile:


test.ORF.xmp (43.8 KB)

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Thanks! I’ll take a look at your history stack.

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So in these I’ve dropped the exposure in the “exposure 1” module and used a gradient mask to just drop the EV value of the from of the of the shirt.

But the more proper way would be to use “tone equalizer” so I just turned off the “exposure 1” and here you can look at the tone equalizer module. Caution, the curve is weird, I could have done a better job with the settings but the look is the same so it’s fine.


test_01.ORF.xmp (45.1 KB)

i now extracted the xmp from the jpeg and there’s the basecurve used in addition to filmicrgb. that doesnt make sense. to brighten up the image you ca add 1.5 EV in exposure module. In the fimlic module yo can give a bit more room to the highlights by increasing white relative exposure to abou +5.5 EV.
in fimlimicrgbs reconstruction tab you cand ecrease the threshold to -0.55 EV to enable this.
And then you can decide if you want to enable hightlight reconstruction with “Reconstruct in LCh” or disable it - that controls the brightness of the highlights on the shirt

test.ORF.xmp (7.2 KB)

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Thanks!

Shadow/Highlight recovery is a weak link in DT (my opinion/may be ignorance) there is no easy way, the shadow/Highlight module in DT is for a very minor corrections. Corrected using Capture one, even the blue tint is not there in a white shirt!

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If by “recovery” you mean reconstruction, then yes, but otherwise you should filmic.

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But that’s not the look applied by the LUT. The LUT brings up the blacks and darkens the shadows. If you don’t want to have this behaviour then you‘d better don’t apply this LUT

That’s a very nice LUT. Where does it come from? Is it freely licensed?

Hi @anon98727765 and welcome!

would it be possible to make this change permanent?

At least semi-permanent :slight_smile:
If you’d like, I can talk (please read write) you through the procedure on how to do it…

Have fun!
Claes in Lund, Sweden