Hello Martin,
darktable is an Open Source project, this means that the documentation is also Open Source. One way to contribute to an Open Source project is to improve the documentation!
For tooltips, you can open bugs and suggest an improved text. For the manual you can download the git tree and improve it directly.
Even just opening a bug saying you don’t understand some part of the manual would be helpful. @elstoc started one for chapter 1 of the manual.
OK … I guess I asked for that, Andreas! However I was not so much berating the existing documentation as much as praising Aurelien’s very helpful tooltips.
I can see a conundrum in that a developer who knows and understands the source well will likely write terse documentation, effectively as an aide-memoire; whereas a plodder like me – who could do with more spoon-feeding, hand-holding, whatever metaphor you choose – will struggle to be able to adequately document something s/he does not understand well.
Yes, I could take the time to become familiar with the code and understand exactly what it does. This assumes I have the capacity (not just time, also intellectual, conceptual, mathematical). But, assuming for a moment that I have that capacity, I would then become more prone to writing terse documentation.
To quote the timeless “Real programmers don’t use Pascal”:
Real programmers don’t document; the code is obvious.
None of this is meant to be an excuse for not contributing to the project, merely a “Don’t hurt me” kind of weak defense! Maybe I’ll be able to make a few suggestions on documentation, but I’m feeling rather out of my depth at the moment.
Anyway, thanks for the encouragement to get onboard. 
Fantastic! Good job!
I have a question: If a higher value on the “hardness” slider makes the highlights brighter and the shadows darker, is that not another way of saying you increased global contrast? So what is the difference between the hardness slider and the contrast slider?
PS: Why don’t you promote your librapay campaign harder in your videos? I think you deserve a decent wage for your job.
Not really. Hardness is more like the “texture” of the contrast, it’s a bit hard to explain.
Because I always forget. Arti-scientist here, not marketer ^^
This is an interesting point. If you look at the filmic “graph”, you see that increasing hardness results in a greater Y value at every X point, except where Y is zero. So surely the shadows would go lighter not darker? And yet I think the preview is showing darker. Please can someone explain!
No, it’s more complicated, because the mapping at the end of filmic takes the hardness into account, such that scene 18% get remapped to display 18% no matter what.
There is really no intuitive way to explain what hardness does, it makes sense only if you compare it to paper grade when doing darkroom analog printing. That’s why I compare it to a contrast “texture”.
Just don’t mistake it with the “true” contrast parameter.
To try and understand this more, I thought I’d draw some graphs at different H (hardness) values, since I recently shot an xrite checker. So I processed the shot below, concentrating on the top row of grey values, which are not raw-clipped, and processed them hopefully sensibly. I then used the dt colour picker in Lab mode to sample the top row. Looking at the results, I don’t think it’s worth drawing graphs, but it is showing the black patch goes lighter as H increases. Filmic chose H=1.56 when I processed the shot. All I then did was alter H to 1.17 (25% less) and 1.95 (25% more) to get three versions to sample. Here are the H values and L values of the patches -
1.17 zero 47.16 65.37 77.34 85.01 89.66
1.56 5.15 47.28 65.44 78.75 86.92 91.39
1.95 6.06 47.26 66.28 81.16 89.84 94.02
Here is the shot being used and the XMP FWIW -
Hey Aurelien, great work !!! Looking forward to the new release.
I watched your video. I seem to miss something here : under ‘Look’ there’s no slider anymore for ‘extreme luminance saturation’, which I used a lot. How to tackle this in Filmic V4 ? Thanks in advance.
It’s now “middle tones saturation”. The logic is different: v3 allowed you to give non-zero saturation for extreme luminances, while keeping midtones unchanged, v4 forces extreme luminances to zero saturation, but let you increase it in midtones instead.
How did you manage the latitude along ? Usually, it’s impossible to keep the latitude the same when hardness is changing (that is, without clipping), so it’s really hard to compare things.
I didn’t notice any problem with latitude, I left it at the default of 33%. Just looking again now, I can move hardness all over the range and latitude stays at 33. You may have noticed I reduced the dynamic range quite a lot (to 37%) so as not to have the black and white patches clipping. (The new Contrast default of 1.5 seems quite high by the way?)
And people wonder why not more people use darktable for processing 
BTW, darktable 4.0 user manual - darktable (latest version: 2.4) has no edit function. That’s where a new user would look first I guess.
The latest manual is here: “darktable 3.4” in the darktable usermanual which you can find by click “Resources” on the home page.
While those of us that know the program can guess what new users need to know, its better if new users tell us what they think is missing, or better yet, write those missing bits while their understanding is fresh.
You have a stale bookmark. Go to https://www.darktable.org/, click resources in the top menu, click English in the next page presented, and you will be taken to “darktable 3.4” in the darktable usermanual as @paperdigits mentioned.
Nope, that was the top hit on google. I wonder why darktable.org doesn’t put the 3.0 manual in that spot as most people probably use google.
Interesting…I see that. My normal practice is to go to a product’s home page and then find the doc from there, since that avoids stale links and “unofficial” versions of the doc. It’s saved me from a lot of blind alleys, but I recognize that just because that’s what I do doesn’t mean that everyone does the same. Maybe a redirect on the darktable.org web site to the appropriate Gitlab page would be beneficial.
The heading of “darktable 2.4” didn’t indicate that it might be the wrong version?
Perhaps someone with write access to the documentation can put a red banner warning people that the 2.4 documentation is stale?
Like python does for legacy versions: Argparse Tutorial — Python 2.7.18 documentation
Just added a issue on the github tracker Add a warning banner to old versions of the manual · Issue #5374 · darktable-org/darktable · GitHub
I’ve just commented the issue. Perhaps, I can contribute to darktable (finally!) 
