Darktable Episode 77: New workflow with enhanced sigmoid and new primaries module

[@Maxime-ho9iv]

Holy Jesus. I didn’t play with the new version of Darktable yet (too busy actually working on my photography) but those additions are massive. The RGB primaries may be what I actually needed for color grading, which is something that always felt missing in Darktable until now. I mean it may still not be enough (I wish we would have something like Davinci Resolve) but it’s a nice step in the right direction.

[@ytskt]

Hands down my favourite Darktable channel. Thanks for sharing!

[@themattiemisfit]

YES. THANK YOU. The kinds of examples I have been looking for in Darktable tutorials! I shoot a lot of concerts and the lighting can be really extreme and I have been struggling with the colors, sometimes I don't want to take the easy route with black&white! Thank you, I'm excited to try these suggestions with sigmoid now!

[@Giles29]

Wow. This really improved my understanding of what the RGB Primaries module does. Thanks a ton, Boris.

[@elliotswain8527]

improvements to darktable, community, and content like yours is why I have stuck with Darktable. Thanks Boris.

[@lechindianer]

The moment you started moving the blue slider on the concert photo... magic happened. Wow

[@rolandrainer3639]

Wieder ein fantastisches Video, Boris! Vielen Dank, hab wieder viel gelernt.

[@PhilippLutz]

What a episode again! After a while I was asking myself "well, what can we do with rgb primaries now?" your video takes a turn towards rgb primaries and everything starts to make sense now! Thanks again for this well explained and informative video Boris! P.S.: I'd happily sign up for a youtube membership (or patreon) for supporting your great videos. After all it's a lot of work and it's even free for everybody.

[@igoreberhardt3327]

As always. Very good approach!

[@Eigil_Skovgaard]

Thank you, Boris, and all the best for you in the new year too.

[@us1tas]

Demonstrative examples and clear explanation

[@ShootingAndReloading]

Thanks for the video - excellent description of how to use these new tools :)

[@arnaudm.7404]

Thanks very much for this episode. And all the best for you in the new year too. Strongly the next episode.

[@maciejlewicki9084]

Oh dear, I was struggling so much with those blue lights in the past! And your tips come just in time to still save some of the photos with Christmas lights :)

[@bernym4047]

As usual with your videos, excellently and clearly explained. Two very powerful modules that could save some time. Thank you and a Happy New Year.

[@krism20]

Today I was thinking about your channel, and.. Bingo, thanks Darkmaster

[@photomoods-mariobolz8801]

Ein gesundes neues Jahr Boris , danke dir für die Erklärung. Lieben Gruß Marioooooo

[@huubdegroot]

Wow Boris, again fantastic explaination!!! Thank you soo much!! Love your videos and I use them a lot!!!

[@nofati4474]

Great improvement and Great tutorial! I was kept trying with this kind of editing by using channel mixer in color calibration module... It was too hard to understand and takes too long time. This new method clearly makes more sense in line with non-color expert's intuition. Thank you Boris.

[@mirukuteea]

Why are we so obsessed with restoring colors to how a camera responses to real life colors? For example the highlight desaturation. My naked eyes don't see bright saturated red as desaturated red in real life but a camera does. A color's luminance can also appear as Helmholtz-Kohlrausch effect has stated. From what I've seen the academic approach seems really bent on hue preserving as well (sometimes I couldn't even see Bezold-Brücke shift in some of the graded works). I feel like I'm going crazy.

[@thomaswirtl4446]

Many thanks for great explaination.

[@ArminHirmer]

very interesting, thank you a lot

[@lphilpot01]

Very clear and obvious explanations / demonstrations! I'm a past darktable user -- and maybe again, future, who knows -- so I'm "filing this mentally" for possible later use. Even though I don't use darktable right now I like to try to stay abreast of what's possible. Excellent video.

[@wishingluck]

Thanks for your explanations - up to now I always used filmic, but the options for selective color treatment make me think to give sigmoid a try. Sounds way more straightforward than a complex filmic/color balance RGB combination.

[@jonieder50]

Would be cool the see the updated sigmoid and rgb primaries module in a full image process that involves a more artistic approach like in your video series on color harmonies :)

[@Chris-St-DE]

Colour Science !

[@michalkvasnicka3290]

Wow. Awesome as always. Nonetheless, I have two questions: 1. How do the three white-balancing methods (color calibration, RGB primaries, and sigmoid) work together? 2. Did you eventually switched from filmic to sigmoid? Anyway, make thanks and blessed new year. Michal

[@s7habo]

1. As before. There is no change. Per channel color processing in Sigmoid only offers better handling of effects of our perception if desired and deals better with colors outside gamut. It does not change the RGB ratio. Rgb primaries module works on the same principle as channel mixer in color calibration module (R,G and B tabs). However, it offers more intuitive handling. 2. Yes, but whether I stay with Sigmoid remains to be seen. I'm still playing with it.

[@lxhk3595]

Boris, for me your educational work is as important as Darktable the tool itself. If nobody explain you what a hammer does it is more or less useless. One question, can you recommend readings about these perceptual effects that you use in your photo development?

[@s7habo]

en.wikipedia.org/wiki/Abney_effect en.wikipedia.org/wiki/Bezold%E2%80%93Br%C3%BCcke_shift

[@cliffnieuwenhuis8638]

Thank you for the excellent video. I'd like to see you comment on how the using RGB sliders in the Sigmoid module affects other modules. For example, sometimes you move a module after another module in the pipeline because you want the effects of one module to feed the next. So for example if you wanted to use tone curves to adjust contrast in the smoke in your first "blue" photo, would you need to move the tone curve module above (after) Sigmoid? Or would you simply adjust Sigmoid first so you can see the smoke better and then go the tone curve module and make adjustments without moving it around in the pipeline? Hope that makes sense.

[@s7habo]

Basically, all "corrections" should be made in the so-called pre-formation area, i.e. hierarchically before the tone mapper (in this case Sigmoid) because you are in a very wide, linear and unbound color space (Rec 2020 RGB) and all corrections are more or less physically correct there. Tone-mapper ensures that everything "stays in the frame" This does not mean that you cannot continue working after Sigmoid. But, after Sigmoid you no longer have gamut protection, which can quickly lead to clipping and you can also cause other artifacts. To take your example, if I want to create contrast myself, I would reduce it in Sigmoid and would then use e.g. brilliance sliders in the color balance module, which comes hierarchically before the Sigmoid, to readjust them in shadows, mids and highlights. You can also use tone equalizer for this. If you were to use tone curves after the sigmoid, you wouldn't have a uniform saturation curve and you would get color bending in the smoke. It doesn't make sense to use tone curve before sigmoid, because the output is intended for non-linear color space, which immediately generates the color artifacts. You can possibly use RGB curve in front of the sigmoid, but there is a risk that you will lose local contrasts in highlights.

[@1108pd]

Many thanks Boris. As usual, a very lucid explanation on how to use sigmoid. Is sigmoid overall better than filmic when it comes to processing normal pictures, as against highly skewed colored pictures, like the one you have used to demonstrate? I would like to see you use some examples of using sigmoid on some HDR examples. Thanks again

[@s7habo]

I won't say better, but easier. Sigmiod handles colors better, Filmic handles dynamic range better.

[@MrS3NS3]

Great explanation as always! :) Your Videos help me so much, thanks for this! But i have a other question about Darktable: In my Darktable (Windows10/nVIDIA) i see big differences in contrast between editing the unzoomed photo and the rendered out final version of it. If i edit a photo and it looks good and then render it out it looks flat and dull. Especially in the thumbnails in lighttable. There are a big difference and it looks way more contrasty. If i open it in darkroom it looks way more flat again. And If i zoom in towards 100% i can see the real result. So i can only judge my edit if i zoom in and scroll around. Why is it? Is there anything i can adjust to improve this? it looks like the reason is a combination of the scaler and faster calculations (for speed) that differs from the final render in full quality. Again in short: The smaller the photo is displayed, the more contrast it has. I was hoping that the problem would be fixed in the new version, but unfortunately not. maybe it's a little better.

[@s7habo]

This can have various causes. This may be due to your settings in darktable, color profiles, etc. It is best to address your problem as a bug report here: github.com/darktable-org/darktable/issues

[@Chris-St-DE]

Did u use the whitebalance from the camera for those pics ?

[@s7habo]

No. White balance is done automatically with color calibration module if you select scene-referred (sigmoid) workflow in settings - as I pointed out at the beginning of the video. However, there are situations where it is better to use internal camera's white balance. Then you can select the "as shot in camera" option in the color calibration module. This was not necessary in this video.

[@BorislavPavlov]

Thank you very much for yet another amazing video! I have recently started using Darktable and I learned everything from you. Would you be able to share, how you decided which workflow to use - sigmoid vs filmic? I ofthen wonder about it.

[@s7habo]

It depends on the scene. Filmic has good gamut compression, and you don't lose much local contrast in highlights. New Sigmoid, which I introduced in the video, is unbeatable when it comes to color processing. The fact that you can readjust primary colors individually (per channel) makes the processing of colors much easier. For me as an event photographer, that's a huge advantage. I've been using Sigmoid almost exclusively for almost two months because I wanted to test it out. But it doesn't really matter which tone-mapper you use. It's best to test it out for yourself and then decide on the workflow that suits you.