Editing moments with darktable

[rvietor]

Iirc, in five years some of the options in filmic have changed:

• the “latitude” has had its default changed to 0.1% (it started at 50%?)
• options for the curve fit have changed, at least the “safe” option has been added.

And we have gotten the tone equaliser, which can help here

That gives you more options to keep contrast in the highlights (depending on total dynamic range of your image, of course).

And if you have a large dynamic range to cover, something has to give… (remember the “HDR look”, which seems to have become less popular?)

[EspE1]

Tone equalizer was launched as part of dt 3.0 in december 2019, darktable 3.0.0 released | darktable, so it was already there at the time.
But you’re right about pointing to filmic changes.

[priort (Todd Prior)]

AP has recently revised them again in Ansel setting contrast to 1.18…not sure why that number and latitude back to I think 33 % from what he set the original changes to essentially no latitude when he was working on v7… Must be a tweak …

[rvietor]

Could have a number of reasons, ranging from changes in other modules earlier in the pipe to change in personal preferences on his part…

But it’s easy enough to test in darktable and if needed add a preset

[s7habo (Boris Hajdukovic)]

New episode: sigmoid and contrasts part 2

Darktable Episode 89: sigmoid and contrasts part 2

[TonyBarrett]

Wow. Another. Great!

[Paolo (Paolo Santucci)]

Thanks… it was really useful! I was struggling with sigmoid, but I think you fixed it.

The examples with the gradient image where particularly interesting. I wish there was an optional graph view in the sigmoid module, as a visual aid to understand how the settings are affecting the image.

[Marcsitkin]

Hello Boris- Glad to see you are going to do a new video on the Color Look Up Table module. I remember what an eye opener this module was for me after seeing you use it way back when. As always, thanks for your hard work, I learn something new with each episode.

[priort (Todd Prior)]

If you use the waveform for your scope its pretty easy to see. The sigmoid curve is very simple…bump the skew and it pushes more of the image highlights to white or towards white creating a more harsh transistion. Go the other way and the falloff is more gradual… Contrast is basically a pivot of the linear part of the curve making it steeper or shallower.

Great video follow-up Boris @s7habo. I think these two most recent videos really highlight the use and interaction of 4 key modules in DT ie Sigmoid as a tonemapper, the Tone Eq, color balance and exposure. Really this one is a really good demonstration of the CB module esp for tonal adjustments and I think the mask tab and the fulcrums are under utilized by many users for sure…you demostrated very well how they function and how they can be used…

[s7habo (Boris Hajdukovic)]

@europlatus

Am I right that your use of the “linear invert” instance of Tone EQ is to first compress the dynamic range when the image has a high DR?

Yes.

@europlatus

Would you use it on any other images or just those with a high DR?

Just those with high DR.

@europlatus

Do you tend to use Sigmoid with this neutral curve now?

No. I presented my preset in the last video and I adapt it as needed.

@europlatus

But would you now recommend the neutral preset and use other modules to create a more customized tone curve?

No, because I think the contrast that Sigmoid offers is a good start and you can quickly adjust it yourself if necessary. But, if this makes the work easier for some people then you can also use the tone curve for all contrast.

@europlatus

In the threads I mentioned in my previous post, I had talked about a scenario where you might want to work on perhaps 2EV of the dynamic range (e.g. just the clouds in the sky, or the ripples on a sandy beach). I talked about restricting Tone EQ to just these 2EV, and therefore having all nodes available for adjusting these 2EV. This involves quite “extreme” values for the Tone EQ mask, and is not always easy to dial in properly. Would you ever try to do something like this with Tone EQ, or would you probably just use a parametric mask to restrict the module’s effect?

That will be one of the topics in the next episode.

@europlatus

How would you go about adding contrast at the extreme ends of the dynamic range (brightest brights and darkest darks)? Do you think local contrast modules are more suited to this rather than modules such as Tone EQ and Color Balance RGB?

I can’t say much about that until I see the specific examples.

[Dinobe]

Another masterclass in Darktable. Thank you very much!

[priort (Todd Prior)]

@europlatus

Do you think local contrast modules are more suited to this rather than modules such as Tone EQ and Color Balance RGB?

I think if I do understand you it will be a module or technique that enhances local contrast… Local contrast is an enhancement that involves looking at a pixel and the surrounding pixels and using some math to enhance the perception of local contrast which I believe in human vision is one of the things we are most sensitive to… even trying to make a tight adjustment in the tone eq I don’t think will totally replicate this…it has a guided filter but that is not the same … Looking forward to being schooled by Boris…

I’m sure there are lots of demonstrations of this but there was a video I watched recently on Affinity Photo and the presenter was explaining local contrast and showing in a few images that you can do all kinds of tone mapping and contrast adjustments and then he did a specific local contrast adjustment on a sky and brick wall and both clearly have nice fine details enhanced that were not achieved by simply tone mapping or any other standard application of contrast… but as I said always eager to see what Boris presents on this…

[bminney]

How many of us eagerly await another Boris video! I learn so much from his tutorials. Hope @s7habo doesn’t feel under pressure to keep these coming.

[TonyBarrett]

Sorry

[s7habo (Boris Hajdukovic)]

[TonyBarrett]

Giggle

[priort (Todd Prior)]

https://images.app.goo.gl/czzxj1HfSH1ZoV4q8

[europlatus]

@priort

I think if I do understand you it will be a module or technique that enhances local contrast…

My thinking is it would be somewhere between what you can do with the Tone EQ and what you can do with Local Contrast (or similar module).

Tone EQ is great for working on the whole image or certain smaller tonal ranges of about 4 EV, but it becomes very fiddly for narrow ranges like 2EV. As for Local Contrast, I’m not sure what kind of EV range it works on, but the default settings seem to be very tight. If you use the Bilateral Grid mode of Local Contrast, there is a setting for “coarseness” that seems to increase the tonal range acted on, although this might be more to do with wavelets (I’m not sure!).

Anyway, Boris mentions he will look at this in a future video.

@s7habo, if you want a sample image, let me know. I’m thinking of something with clouds or an interesting sandy beach where you might want to emphasize highlights. Usually I don’t really want to add detail in highlights, but there are exceptions.

[s7habo (Boris Hajdukovic)]

@europlatus

if you want a sample image, let me know. I’m thinking of something with clouds or an interesting sandy beach where you might want to emphasize highlights. Usually I don’t really want to add detail in highlights, but there are exceptions.

Yes, please! I’ll have a look at them. You can also specify exactly what you want to achieve and we’ll see.

[davidvj (David Vincent-Jones)]

Is the ‘gray scale’ image available for practice purposes? The one that Boris used in the last video.