Seahorse brown/red color disappears

I’m an underwater photographer learning to use darktable. Sometimes the camera JPEG looks already pretty good, and I just want to do some minor edits like removing backscatter (dust particles lighted up by the strobe). For some photos I’m struggling, because some of the color gets lost. Especially photos with subjects with a red/brown tint become more yellow when using filmic rgb or sigmoid. When I try to adjust the white balance the result becomes only worse (e.g. a very unnatural red).

Does anyone have suggestions how to preserve the color? I have attached an example photo of a seahorse.

Original JPEG directly from the camera:

Minimal processing with darktable:

DSC_6297.NEF.xmp (4.9 KB)

DSC_6297.NEF (16.8 MB)

This file is licensed Creative Commons, By-Attribution, Non-Commercial, Share-Alike.


I probably messed with it too much, but I got it to this (trying for the red you are asking for). dt 4.4.2

DSC_6297.NEF.xmp (6.4 KB)

Hi, here my version and as I don’t have a ‘real’ reference, it is my interpretation using the latest nightly.

You can play with ‘color balance RGB’ and the new amazing ‘rgb primaries’ in 4.5.0.

DSC_6297.NEF.xmp (10.6 KB)

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The exposure looks a bit different in your two examples which will exaggerate things but you might in the case of this one just be able to bump the red in the colorfulness… this could make it more yellow though… there are lots of options to tweak it … I’ll maybe try later…

EDIT… less yellow ???

Tried to subdue the background while popping the subject. :slight_smile:


My edit.

DSC_6297.NEF.xmp (16.2 KB)

Thanks for share.

Greetings from Havana, Cuba.

GIMP. Increased all the colours using Channel Mixer.

darktable 4.5.0

DSC_6297.NEF.xmp (10.3 KB)

Cool image, thanks!

seahorse-DSC_6297.NEF.xmp (24.0 KB)
dt 4.5

I have noticed that as well, however it has nothing to do with either filmic or sigmoid. In the case of my camera (Canon 5D mk. II) it seems to be the camera reference matrix that’s a little off. When I added custom coefficients to WB, it got mostly fixed.

White balance is not there to “creatively” adjust the colors. Use it to get a neutral starting point for further adjustments.

My attempt:

Seahorse DSC_6297.NEF.xmp (10.8 KB)
DT 4.4.2

I think I got pretty close to the camera JPEG, but with much better clarity.
I started by adding some color with color balance rgb. This makes it easier to see what is going on when white balancing.
For white balance, I first used the auto picker in color calibration and, using the barnacles as reference, adjusted the chroma until it looked reasonable. The classic white balance module I left at camera reference.
This was still a bit on the green side, so I used the channel mixer to remove some green in the red areas.
The rest is just filmic auto tune, lens correction and sharpen demosaic D&S preset.

Before removing the green cast:

It’s not filmic or sigmoid taking away contrast and saturation – it’s your camera adding them to the JPG.
With both filmic and sigmoid disabled, only increasing exposure (ignore any clipped highlights):

You can change colours on the ‘4 ways’ tab of color balance rgb (and you can apply masks for tonal ranges, colours or shapes, or a mix of those, as well).

DSC_6297_01.NEF.xmp (13.1 KB)


I am travelling at the moment so I can’t edit your image. However, try using sigmoid instead of filmic and see if that improves your color. Filmic by default gives dull colors that don’t compare well to the cameras jpgs. Sigmoid gives stronger colors straight out of the box.

They both sort of drive it more yellowish away from red/brown noted by the OP but it is not hard to tweak… not having seen the creature in person and under that provided lighting likely hinders making a completely correct edit no matter what modules you throw at it. The best you can do is try an adjustment that is in line with the comments made by the OP… and trying to offer a correction for that

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Is this the sort of problem the primary sliders in sigmoid are meant to help with or not?

This is a DCP job, without DCP profile in Darktable is possible to use the color look up table “hand tuned”

DSC_6297.NEF.xmp (9.9 KB)

The color of these seahorse can vary from yellow (somewhat like in my darktable edit) to very dark brown (almost black), but most of them are somewhere in between and have a more brown color. So it’s not like the yellow in my edit looks unnatural. I just happen to like the color of the camera JPEG because it results a nice contrast against the neutral (mostly gray and almost de-saturated) background, which is a bit less the case in my yellow edit. The color of the camera JPEG is also pretty close to the real color.

When I start to process the image with darktable to bring back the red/brown color, I quickly end up with a very unnatural red color cast in the other parts of the image. You can also see this is some of the edits. Especially the background starts to gain a bit of color too.

This is not the only photo where I notice this. Certainly not in every image, but with some of them and always with brown/red subjects. Another example:

Original JPEG directly from the camera:

Processed with darktable:

I’m very satisfied with the result, except for the fact that color of the insect is a bit more washed out. The camera JPEG has again more brown/red, and I haven’t really found a way to preserve that look, without ruining the color of the seaweed.

What’s a DCP Profile? How did you create that color lookup table? The result is almost identical to my camera JPEG!

You can use parametric, drawn or combined masks to limit the effect, or the color lookup table module to shift a small range of hues.

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Try the skin tones patches in CLUT…these are good for tweaking browns in your images… You can actually select your color from the image is you shift click…

Please keep in mind that brown is just a dark orange. So, if you increase exposure/brightness, brown tones become orange. If you compare edits
with respect to color, the respective images should be similar in brightness.

Her the same image with just a change of brightness via a tone curve.

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