Yeah indeed that’s an issue. Since this is purely a usability issue (having related parameters in different modules) it should be addressed by the UI rather than changing the pipeline, and you can already open both modules (although it’s not super intuitive how), or maybe have them in the quick-access panel. That said I’m not totally convinced that having the option wouldn’t help in some cases, specially since changing exposure can be problematic with you have masks and stuff. I can put an exposure module before sigmoid to test though.
You should put an exposure module before it… There is a reason it’s there by default 
.
It’s also one of the things you should set before doing anything else… although I do realize it may be hard to judge if you set it ‘right’ from the start.
1 Like
One trick to nail the exposure is the following:
- Set the contrast in sigmoid to something very high like 5.0 - 10.0 (use keys to type it in as its outside of the soft bounds)
You should now have a very contrasty image with mostly black and white stuff.
-
Adjust your exposure such that your subject (face etc) is right in the sweet spot between white and black.
-
Reset the sigmoid contrast value and work from there.
Helped me to get a grasp on where middle grey is.
Any further adjustments is preferably added in new modules so that you always can go back to that initial normalization.
11 Likes
In my opinion, this is the number one issue folks have either filmic or sigmoid. Determining the middle gray when you have a large dynamic range image is really important and mostly an artistic choice.
1 Like
Just out of curiosity, how did you generate these images, did you use darktable with a test image with a linear gradient or did you do it different? If the first is the case, how did you do it, which image format did you use and why, how did you ensure that this survives colorin, etc.
It’s just a random image I had, probably downloaded somewhere, thus I wouldn’t read too much into it. For example you can see the “gray area” increase when I boost the exposure, but I’m not sure if that’s due to that particular gradient or to sigmoid.
Great, thanks for the clarification. Sometimes life is less complicated than I thought, but this is not often the case … 
.
I have been using the exposure auto picker. I leave it at 50 to see where it lands Often that is not actually bad. I guess you could refine that and pick a region that you want to be middle grey. With filmic and most of the images I edited 60 % for the overall image was a pretty reliable first guess. I also always started with filmic off so I could see how it visually impacted the image when added . From there filmic auto pickers were usually fine. I have not used Sigmoid enough to know if there is a sweet spot like that is.
2 Likes
That’s what I do too. I actually enable my cube LUT after sigmoid too when I set exposure. After that I dial down the contrast until everything looks fine and then turn off the LUT to see that the image is mostly within gammut before I enable the LUT again.
Hello,
Personally, I opted to fine-tune the black, white and mid-gray settings with the “RGB Levels” module.
To avoid making back and forth, would it not be possible to have a link of the slider of the exposure module.
Greetings from Brussels
Christian
Changing the exposure potentially influences parametric masks, the tone equalizer’s masking settings, color balance rgb (which divides the image into shadows, mid tones and highlights, and has its own mask middle grey fulcrum, threshold white fulcrum and contrast grey fulcrum controls), and who knows what else. You can’t just wire all brightness-related controls back to exposure.
Hello,
You are right, that’s the reason why I added I slider of the mask exposure compensation, so I can adapt it when I change the exposure at the end of the processing
Greetings from Brussels
Christian
1 Like
Just a thought; have you considered a button or check box to max out the contrast so it is easy to set the exposure for the mid grey? Thanks for the hard work! Cheers.
Haven’t thought about it. Could be something! I’m expecting people to learn though and not need it as much after some time.
It’s a tricky one, the processing should really start with taking the photo (correct exposure, framing an focus solves most problems) and an awareness that our visual system also does image processing that introduces its own artefacts.
Personally I like to try and understand as much of the process as I can, just makes it easier to get the image I intended; not a fan of the computer deciding what I want.
Thanks for your efforts!
Depending on the images I may edit it but there is an autopicker in exposure and I set that to 50% … I will often try it on the whole image first just to see what it lands… if I don’t like that I will choose a subject or area… I find this is often all you need
1 Like
A preset or style would do? That’s how I use it. Not sure a button would add anything.
2 Likes
Good call, thank you.
The 4.2 release is fast approaching… any progress on this?
Working on it! And an answer to the white background image editing problem after that!
Expect a PR before the end of the week
9 Likes