Evaluate the new sigmoid tone mapper just merged into master ...

All v6, either off or max RGB I can’t remember who got what off the top of my head. This were the best versions I could get out of the module either way. I tend not to fall back to old versions.

All good…the new default for v6 will be power norm…maxrgb can make things soft… I wouldn’t say v5 is old really. I think essentially you can have most of the sliders do what they do but you get a different model of control around color and saturation. There may be areas where v6 is somehow considered an advance but in terms of usability that has not really been my experience. In any case I see 5 and 6 as different modes of filmic not really an old vs new…


v6 does seem to do better with preservation set to off than v5 did from my memory. I tend to leave it off these days as I prefer the results. I use to bounce between lum Y and max RGB in the old versions of darktable as off produced some strange effects. I think sigmoid has the advantage for most situations of being a bit more approachable even for those of us used to filmic now and not having to bounce out to color balance RGB as often for tuning is another plus.

I know “all things to all people” isn’t possible but I really think sigmoid is a valuable addition to the darktable package from my brief experimentation. I see it as a better replacement for base curve, maybe something in between? Hopefully it gets merged into the release.

Re. the cyclist pair, these are somewhat different in colour or white balance maybe. It would be interesting to see them with the ground the same in both.

THe option no in v5 and v6 is quite different because of the way they approach saturation. If you have v5 set with no latitude as is the case in v6 it might not be as dramatic but no in v5 will be quite saturated usually where as in v6 it will be much flatter… I personally think sigmoid is nice and will help new users…personally in my hands I get a very similar look to it using v5. I use it set to no and with no latitude… Then I introduce that and shift it towards highlights or shadows as needed and then finally tweak the midtone saturation. This is some extra tweaking but I seem to have a bit more control of shadows and highlights than with sigmoid. I think the more simplistic UI with less options will be appealing esp to new folks and as more people use it and when some documentation that may reveal a nuance or two comes out maybe this will equalize for me… I think the more saturated look of sigmoid with less artifacts as a base starting point is appealing… I find I can have this with v5 filmic and then a bit more control. I am still switching on sigmoid as well just to keep getting a feel for it… bit as for v6 I find I use it less and less … THe new HLR aligo’s do actually seem to help some of the v6 nuances so maybe I might change my thinking yet again with more experience… for me esp when it goes for images with the reds oranges etc… v5 I find is the way to go to have the most options for a starting point. This is similar to sigmoid when you swing the hue preservation slider…

1 Like

I duplicated the image IIRC but I may have discarded the history accidentally, I cannot remember as I was somewhat on a deadline for another thing. I was trying to find some backlit photos to experiment on. But yes it looks like a white balance change to me.

IMGP4070.DNG (45.0 MB) CC BY-NC-SA

Might have found a case were Filmic works better in preserving details: White chalk cliffs.

With Sigmoid there is a noticeable loss of details in the walls, that i did not manage to recover.


I agree from a quick play. I did use Tone eq also with both to try and see if it helped one more so than the other… Filmic gave more detail and contrasted look with the settings I used… thanks for sharing… just another reason to have both options…

As I was saying, the trend seems to be more colour/local contrast with filmic in the pipeline. I say “pipeline” because other modules may influence the outcome (whether due to module interaction, user workflow or user decision tree).

Besides having lower colour/local contrast, which I care about, sigmoid appears to be less saturated, which is subjective based on the look the user likes and the type of photography they are aiming to achieve. Personally, I like the less saturated look with higher colour/local contrast/lines/detail. So a combination of the two methods, if I could have best of both worlds.

The colour/local contrast of filmic could be due to the nice edge preservation that AP developed, but it was probably for something else. I am not sure. Someone could let me know where that was implemented. But if it is that, then sigmoid could borrow for it, or whatever is contributing to that outcome. I think that is what sigmoid is lacking at the moment.

This is interesting… I agree about the loss of detail using sigmoid, however by introducing tone eq and shifting the skew, I found it pretty easy to bring it back.
Below is filmic:

Fixed it now… sorry I’ve lost the .xmp for the filmic but it’s pretty close default settings.

And below now is sigmoid:
IMGP4070.DNG.xmp (12.6 KB)

Again, I agree with this image, but with quite a few of mine the initial impression I get is almost the opposite… but thinking about it, maybe that’s due to my willingness to use tone eq. Which I don’t seem to find the need for as often with filmic. I think all this might be more about my perception/habits than I think!
I’ll try to find an image where I think sigmoid works better and post it here for perusal.

After trying to find an image where I thought sigmoid worked better, I seem to have reached the conclusion that there’s not much in it. Somehow the simplicity and limited controls of sigmoid seem to guide me to a result I’m happy with noticeably quicker than using filmic with the extra controls.
But, that result can be got using filmic too.

In fact, I think with some images I might not have hit on the ‘look’ I get with sigmoid, if I was only using filmic. Not because filmic can’t do it - it can - but because I wouldn’t have ‘thought of it’.

Is it only me thinking along these lines? :smiley:


For me using only tone eq and exposure… I got these images when trying to match them up on the face of the stone. I did go back and use extreme settings in sigmoid and went to rgb ratio to desaturate the color cast in the highlights of the stone… i ended up with them being pretty close … Initially I had taken a different approach and not pushed the skew so hard…


IMGP4070.DNG.xmp (19.0 KB)

xmp is filmic version …turn off and use sigmoid settings above…

So this would not be a final edit but sort of a base comparison… I try to keep all the modules and settings the same …in the end this might not be 100% the be way as the secret sauce for each might be a bit different…

To me where I ended up the deep shadows in the shrubs is better in sigmoid but the rock face and water look better too me… This would be where you could start to target those areas for each different edit to compensate… A new image might offer something different


I actually started to do an edit with filmic and added some modules as I would do… turning filmic on and off really didn’t help nor did sigmoid… I have found this on many edits before esp those where you are trying to examine detail… and I often can actually get a very nice edit without filmic or sigmoid…

1 Like

Yes! I like it. I’ve tried this, but usually I give up… I’m a bit prone to relying on a tonemapper to pull things in line in terms of highlights and so on. Maybe I could try harder!

In the case of this edit it was funny. I set exposure reasonably high for the trees…Then went on to adjust filmic and then then the usual intervention with some tone eq. I often use a few. I find using them with blend modes in color channels is really useful at time for skies, water, foliage tweaks… in the end I was just turning off filmic to sub in sigmoid and I noticed it really didn’t do much and adding sigmoid with this combination of modules was not helpful really either so I just thought well both compress fine detail and the rock is looking okay so I just left them both off… its still not a great edit or anything but it works nicely with my favourite D&S preset “dehaze”

1 Like


  1. Neither of your sigmoid renders removes its flatness compared to filmic. Try flipping between the two in the lightbox or browser tabs. There is a “grey haze” or “less clarity” in sigmoid compared to filmic. Quotations for the loose/imprecise terms.
  2. Attempts to boost details afterward still doesn’t address #1.
  3. The closest analogy I can think of is the difference between on vs off RT capture sharpening, though this isn’t a sharpening problem.

I did the flick, in lightbox and between 100% zoom tabs. The difference I see is contrast. Filmic defaults has a more agressive toe resulting more contrast near black/less detail in shadows. Are you seeing something else?

I would agree I think… basically both can be made to be similar in many edits. I find as you say if we are talking just the defaults that filmic will be darker and more contrasted in the shadows with less detail revealed in the darkest parts and sigmoid is the opposite when it comes to the highlights as it tends to compress more … to get close to flimic it has been my experience that you have to crank up the skew and then tweak contrast. Those observations are comparing at the same exposure, for the shadows you can use more exposure with filmic and offset that aspect of filmic’s dark shadows .

SIgmoid can often be more colorful/saturated out of the gate esp if we are talking v6 filmic…with v5 this is easy to match and control I find. I use the dehaze preset of D&S and it is amazing but the odd time can be a bit too much introducing too much grain/noise but this is less often the case with sigmoid with its softer highlights so its a good match…

We do need to be careful as well with all these comparisons as filmic has choices for the shoulders that impact this quite a bit… I actually use hard for highlight unless they are severe already and safe for the shadows many times… I think the sigmoid look would be more like filmic with both of these set to safe… I think the default in v5 introduced safe as the default and now it is back to hard which is more like older versions of filmic… I think any way…

@nosle Not what I am talking about. Your observation, if true, is easier to deal with than mine.

@priort Sorry, what is D&S? Not a dt user. :space_invader: Dehaze is one strategy but as you note it causes artifacts (and colour shifts).

Diffuse and Sharpen and its called dehaze…to me its just an excellent sharpening preset

EDIT… I do use the haze removal module quite often as well

but I blend in lightness…