Some thoughts on workflows and tone mapper modules

Processing
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You can more or less replicate all tonemappers in Darktable by combining eg base curve (or tone equalizer, preserve details: no), color balance rgb, rgb primaries, in some cases needing multiple instances, with masks.

The point of tonemappers is to get a good starting point with much less effort, in a more robust manner.

It’s like owning a washing machine, vs soaking your clothes in a basin. There is nothing your washing machine can do that you cannot do by hand, it’s just much more effort. The “why tonemappers” question is pretty much like asking why the washing machine was invented.

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A friend sent me a response he generated using AI. I’d like to run the AI’s answer past you.

In summary what it said was that the old method darktable uses, starts by first squashing the raw data within a dynamic range that can be displayed on a screen ie 8 bit colour depth and sRGB. Any subsequent edits you do happen within that squashed space, so are susceptible to processing derived artefacts.

Scene referred processing works differently in that it keeps the data in the full raw space and large colour space while all the edits are done, then only at the very end does it use the tone mapper to compress the final edited file down into the 8 bit sRGB space, and it is clever enough to avoid processing artefacts while doing this.

To my mind this description is reminiscent of the risks of doing further edits on an out of camera jpeg instead of working with say a 48 bit TIFF, then outputting a finished jpeg.

I’m suspicious, it seems too pat that this is what really happens in a raw convertor, even an old school raw convertor. I’m also suspicious in that it is easy enough for me to understand, while I’m mightily struggling to understand other attempts at explaining it to me.

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Does this mean you apply the tone mapper at the very end of your edit process? I’ve always believed that you started with your tone mapper module and tried to do as much of your editing as possible with the tone mapper and only used other modules to finesse details.

Have I had this backwards all this time?

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It’s near the end of the processing pipeline, not necessarily at the end of the editing history.

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Hmmm. Still not sure.

Can you suggest a step by step simple workflow using AGX for an average undemanding image, just to illustrate the steps you would take to turn a dim raw file into an acceptable finished image. Maybe that would help me orientate myself.

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  1. Use exposure to make the midtones an acceptable brightness. Don’t worry about shadows or highlights.
  2. Use AgX’s black relative and white relative sliders to set the shadows and highlights, respectively.

That’s it.

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One is here:

And

And

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That workflow is interesting in several ways, not least of which is because in my habits I never use:

exposure module (I use RGB curves and/or Colour balance RGB Global brilliance slider)

Colour calibration module (the only use I have found for this is for using multiple white balances on different parts of the image with masks. For simple global white balancing, the white balance module works just fine with predictable results while colour cat easily goes wrong).

AGX which I obviously don’t know how to use

Tone equaliser I can use this with the scroll wheel for local lightening/darkening but because it works on the same tones all over the image, I prefer to use RGB curves with drawn masks

I do use RGB colour balance but not for colour other than saturation, instead I use it for tonal adjustments. For colour I use the colour equaliser with the colour picker to adjust single colours at a time. If I need to adjust multiple colours, I create multiple instances and work on the colours as if they were on individual adjustment layers

i do use contrast equalizer for sharpening but not like they suggest. The detailed operation of the module is not intuitive to me, so I use the presets.

Exactly the same with the diffuse and sharpen module, it is utterly impenetrable, so I use the presets which are useful.

This workflow is sufficiently alien it would take an immense effort of will to swap to it, one I won’t make unless I completely understand the why of why I should do so - which is essentially the problem I’m trying to get my head around in these threads and not making much progress on despite everyone’s stirling efforts.

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p.s.

Forum operational question: it looks like you edited your previous post after your posted it. I’ve wanted to edit several of my posts but I can’t find a way to do it…

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I watched the Keven Ajili video. Another frustrating experience. It’s just not something I can understand and learn from. He starts thrashing around moving different sliders rapidly back and forth while babbling and it isn’t clear what is happening other, than that several sliders in different modules basically do the same, or near same thing. It’s all far too complicated and contradictory for my taste.

It seems to be a symptom of darktable that it shares with photoshop. There are many ways of doing basically the same thing and no clue as to why you should prefer one way over another and every user seems to have their own way of doing things. This is described as a power of darktable but I suspect that for 99% of photographers it’s actually a turn-off.

I’ve committed to darktable for the last 6 years because I’m not going anywhere near adobe’s ransomware again, but in reality what I want is for darktable to be a version of lightroom with dT’s powerful masking tools. All these complicated modules with their dozens of sliders, dropdowns with incomprehensible technical terms and so on are a real barrier to understanding.

That’s why I have tried to develop a personal dT workflow that is SIMPLE to understand, so I know exactly what I am doing and why.

I’m inspired by the Charlie Cramer/Bruce Percy approach to editing, which is to eschew global editing at all, and do all editing as a series of local edits.

Bruce has videos in which he walks through his photoshop approach. Basically he opens a file, creates a bunch of adjustment layers, does a selection/mask, one per layer and does a single local edit using only curves. Then he switches to another layer and another selection and does another edit again using curves. And so on for all the different parts of the image.

This method gives him absolute control over his editing process and it is easy to switch a layer on and off to see what effect it has. I want to replicate that approach using darktable, hence my workflow based on creating multiple instances of the RGB curves tool, each with its own mask.

Am I ok with that as an approach, even if I ignore the tone mapper? i believe it works from eyeballing my files but watching videos and reading guides fundamentally undermines my confidence. Does what I do break the way darktable is supposed to work, leading to poor quality files (I don’t think my files are poor quality, but I could be fooling myself)?

If I am going to switch to these recommended workflows, I need to understand them first, and so far I’ve made a terrible job of doing that…

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This is what a tone mapper tries to take care of. You understand the tone mapper in terms of film (where the film medium itself tonemaps the scene luminance into the recording medium), but with digital the capture stays linear, and you have very fine control over the roll off in both highlights and shadows.

No I am saying that all the images you’ve shared look like they are they do not contain values that exceed the display medium, so it is much easier not to use a tone mapper, as there are many modules that can pleasingly stretch the histogram (there are fewer modules than can compress the historgram pleasingly IMHO).

nobody is asking you to swap it. You came here and asked about it, people have tried to explain it to you, but you only seem interested in refuting what people are telling you and asserting your own way of doing things (which is fine). If you want to keep doing things your own way, then go for it, that is the beauty of darktable. But if you’re going to engage people and ask questions, then you need to be willing and open to taking that new information and trying to make sense of it and make it work, which honestly it seems like you’re not open to that. This is the part where people are getting frustrated.

Yes it is a “toolbox” approach.

For you it might be a turn off and that is fine. But there is no data to back up this claim. It seems probably that the people who dislike this approach immensely just go to Lightroom or Capture One or something else that have tailored the editing experience towards speed and ease of use. And that’s fine too.

You can continue to use it however you want, and I guess you can achieve this with an opinionated set of modules. If that is what you want and you’re getting that, that is good. If you’re asserting that we should make darktable into what you’re suggesting, you’re going to get shouted out.

As I’m sure you already know: trust your eyes. If you’re happy with your workflow, then go for it.

If you want to learn something new or learn why we tell people to work in this way, we’re open to helping, but, again, you have to be open to learning.

Did you try this?

You are new and so not possess the social clout needed to edit posts. We configured this to combat spam, and it has had a negative effect on usage of the forum. Send your thank-you cards to Open AI et al.

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If you’re referring to my workflow, that’s fine. I organized it into concepts using some example tools (specifically choosing some new to 5.4 tools) but you could replace those tools based on your preference. Your workflow that you outlined in the original post generally follows the same concepts. My workflow post is intended to be a reliable starting point, not the end-all be-all workflow that everyone should use.

To be honest, the sample images you provided look quite nice. Whether they use a scene-referred tone mapper or any of the other tools in my workflow is immaterial to me. Your results look good. None of the tools you are using are going away.

You can always create a duplicate of one of your images and try out a different workflow and compare the results. Even if you don’t fully understand the inner workings of the tone mappers or other modules, you can still give it a try and see the results for yourself. You admit that you don’t fully understand the diffuse or sharpen module, but you still use it with presets. Try the same approach with the agx module using the “auto tune levels” button.

The way I actually use the agx tone mapper is much simpler: I usually just raise the shoulder power a bit to increase contrast in the highlights that can be lost using a flash. The rest of the general contrast adjustment is done in color balance RGB’s brilliance sliders. If people think that’s wrong, that’s fine, I don’t care :slight_smile:

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I wish this forum had a simple quote button. Try as I may hovering over your text I can’t get the pop up box to re-appear. So I’m doing the hard way, cutting and pasting your remarks:

" No I am saying that all the images you’ve shared look like they are they do not contain values that exceed the display medium, so it is much easier not to use a tone mapper, as there are many modules that can pleasingly stretch the histogram (there are fewer modules than can compress the historgram pleasingly IMHO)."

---- does this mean that the purpose of the tone mapper is to handle very high dynamic range images?

"nobody is asking you to swap it. You came here and asked about it, people have tried to explain it to you, but you only seem interested in refuting what people are telling you and asserting your own way of doing things (which is fine). "

---- that’s a bit unfair. I’m not wanting to refute what people say, I’m wanting to understand what they are saying. What you are saying about refuting and unwillingness to learn is symptoms of my frustration of not being able to make sense of what people are saying.

“If you’re asserting that we should make darktable into what you’re suggesting, you’re going to get shouted out.”

---- I’m not demanding that at all. If I were, the easiest response would be “fork the product and rebuild in your own image”. It’s not like that hasn’t been done :slight_smile:

No, what I’m saying is that darktable is flexible and I want to configure it to my way of working (it would be nice if you could re-order the modules in the UI without affecting the pixelpipe order. Perhaps a little toggle in the settings?) and largely I have. But I’m concerned that might be a mistake and is working against darktable so I am reconsidering my approach in the light of AGX. But in order to do so responsibly, I need to feel I understand what the new approach actually is and what role the tone mapper plays. Some people have tried to explain this and I have failed to understand (still). Some other people have advised not worrying about it and just using it in some super simple way (advice that concerns me even more because it means accepting working in the dark).

"1. Use exposure to make the midtones an acceptable brightness. Don’t worry about shadows or highlights.

  1. Use AgX’s black relative and white relative sliders to set the shadows and highlights, respectively.

That’s it.

Did you try this? "

— I think this is roughly what I do when I occasionally use filmic to control blown highlights. I just adjust those relative exposure sliders randomly until something looks better.

"You are new and so not possess the social clout needed to edit posts. "

---- A pity. Three things I have noticed today about the forum software that could be better:

  1. It would really benefit from a threaded view. Conducting technical discussions with multiple people is painful when the posts all end up interleaved.

  2. A simple quote button next to the reply button would be brilliant. The hovering pop up is really hit or miss

  3. The ability to edit your own posts if they have not been replied to. Having to reply to your own posts just to correct a typo is a pain.

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That’s worth experimenting with, I agree. Good suggestion

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You get more out of Darktable the more you put in. If you don’t want to do that, that’s perfectly fine. Nobody’s forcing you, and there’s no marketing department telling you “you’re holding it wrong”, to get you to pay for the next upgrade.

The conflict here is not about how you use Darktable. Do what you want. It’s that you asked a question, but fight the answers. Appealing to “99% of photographers” does not help you in a forum explicitly about the remainder “1%”. Adobe is really good at serving the 99%, and will happily take their money.

People keep telling you that there are better ways to achieve your goals in Darktable. But we can only show you that path. You need to walk it yourself.

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ps.

here we go again, oh for an edit function…

How long do you have to be around to count as “not new”. I’ve been posting here for two years or so…

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That’s just me getting frustrated and saying something annoying. Take no notice.

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Highlight the text and the quote button pops up, click it and the quote text will be added to your post.

The tone mapper is for controlling the transition of linear space into non-linear space. In film, the film itself handles this, and you seem to understand that really well. Imagine that the non-linear response of film is delayed until you’re in darktable, and that you have a lot of control over that non-linear transition.

I use the tone mapper to set the over all contrast for my images. For me that usually means stretching the histogram to give decent over all contrast. Seems your images are similar.

I choose the tone mapper to control the over all contrast because it works well for all types of images, e.g. when I have a lot of dynamic range, the tone mapper is still a great too, where as tools like the tone curve start to fall apart.

I think it’d be much better received here if you wrote what your understanding is as you gain more knowledge. This will be iterative. Continually saying “I don’t get it but I do it this way” is only going to frustrate others trying to help you.

I think it will click for you soon, as you seem to have excellent knowledge of film technique, and this isn’t really that different, its just that all the things in film that were not very editable, are now extremely flexible and editable.

Yes you are correct. But I find AgX much easier to use than filmic. Also it seems you have not tried this. Why don’t you try it?

Well we don’t make the forum software, we just it.

You can see replies to a particular post, if there are any, by click the “1 Reply” button at the bottom left hand part of any particular post that has replys to it.

Highlight the text and it pops up every time.

Clearing the participation bar will earn you the rights to edit.

It is not a length of time, but the amount of participation.

We’d rather that you don’t type it in the first place. You’re shifting the the burden of your frustrations onto us, when it is actually your problem not ours. If you’re frustrated, get up and go outside for a moment.

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Someone elsewhere gave me a link to study. I’ve only glanced at the index. Before I dive in, do you think it will be helpful with respect to darktable?

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Folks, let’s stop the hand-waving. :angry:

I’ve been questioning the devs on pixls.us and I can’t make much sense of what they say as to what AGX does other than when they resort to handwavy statements
(https://www.dpreview.com/forums/threads/in-need-of-the-insight-of-a-jim-or-other-engineer-scientist.4825840/post-68556703)

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