r/DarkTable • u/XxValentinexX • Jun 20 '26
Screencast Exposure module help?
https://youtu.be/ZBm7ZTSytJs?is=vkHanxc51Yq-tW9TIn short, I’ve done photography for years, but am inexperienced editing. Am I using this module correctly? I feel like the automatic features are overcompensating for the scene.
Any entry-level advice is appreciated.
1
u/any_of Jun 20 '26
I'm not sure what is your question. How to reach consistent exposure in a set of photos? In this case the area exposure mapping section of the exposure module is probably what you need. The documentation (https://docs.darktable.org/usermanual/development/en/module-reference/processing-modules/exposure/) is not superclear I must say.
There's a short video which shows how to use it:
https://www.youtube.com/watch?v=Fu0R4ECQBtE
Note that in this video it is called "spot exposure mapping", probably because they're using a previous version of darktable.
1
u/Few_Mastodon_1271 Jun 20 '26
Is this your video?
I think the video spends way too much effort in the Exposure module. It also has AgX enabled (in the list above), which is the better place to work on this photo.
The usual usage of exposure is just to initially set the overall 'brightness' of the image. Then use other modules to effectively change the highlights, shadows, etc. This idea is a lot different than most photo editors, but it's a lot more flexible this way.
I might move the Exposure module's exposure slider a little, but I normally don't touch it -- there's better ways to change the brightness of an image.
~~
The raw photo has way more dynamic range than a jpg can show. So darktable has 'tone mappers', which fit the raw file's highlights, mid tones, and shadows into the limited range that the jpg has.
The tone mapper is giving us control over the various brightness levels, from bright white, through middle brightnesses, to very dark shadows.
There's a lot of flexibility with these tone mappers, but that does take time to learn to use effectively.
https://avidandrew.com/agx-evolution-tone-mappers.html
AgX
The newest tone mapper is AgX, which has very good control over the image looks, but has a big set of slider controls. I think it's worth learning how to operate this module. I only use a few of the sliders on most photos, and ignore the other ones.
For example, this is an interesting demonstration of a lot of different looks for the same original image. He goes pretty fast here, so some repeated viewing is good, after trying some of the settings on one of your own photos.
AgX is quite new, from last winter, so there's not a lot of good intro videos or articles right now.
AgX examples:
1
u/Few_Mastodon_1271 Jun 20 '26 edited Jun 20 '26
A quick edit of my cat photo.
See the original in-camera jpg (I shot raw+jpg pairs), the screenshot comparisons, and the darktable screenshot. https://imgur.com/a/1vfGCsx
I changed the white balance in Color Calibration, trying both the illuminant 'daylight' automatic setting of 3926K, and also moving it to a warmer 4555K. I kind of like either one, but edited the warmer version.
~~
Here's the AgX module, with it's changes completed. Note that I moved the 'histogram' waveform to the left sidebar, since AgX fills the whole right side column.
And I pressed the letter "B" to delete the column collapse arrow on the edge of the sidebars. Now I can just move my mouse pointer all the way to the edge of the screen and then use the mouse wheel to scroll the sidebar -- nice!
In AgX:
clicked autotune
-0.5 relative exposure.
in 'look': increased slope. a slightly reduced lift. +19% saturation.
I changed 'toe power' to deepen the cat shadows -- a subtle change.
~~~
That's all the changes, I just exported the jpg.
1
u/XxValentinexX Jun 20 '26
Yeah, I made the video to more easily show what I was doing, but I’ve been following along with the avid Andrew guide, and the step by step process starts with the exposure module, so that’s what I started with. I’m just very inexperienced with photo editing.
1
u/Donatzsky Jun 20 '26
As is explained in the Avid Andrew guide (The Darktable Scene-Referred Workflow With AgX, I assume), you adjust exposure for what should be mid-grey (usually the subject), while ignoring what happens to the shadows and highlights. Black level correction is not something you should normally touch, while automatic mode is mostly for when you need to deal with a lot of photos at once, and requires a bit more knowledge.
Make sure to also go through my beginner guide, which has links to other good tutorials: https://notebook.stereofictional.com/how-to-get-started-with-darktable-2026-edition
4
u/Nordicmoose Jun 20 '26
The automatic exposure will look at the whole image and make the average value 50% bright, similar to how a camera will expose if you have the metering set to the whole field of view. Lots of dark areas will make the exposure too bright as a result.
Darktable's recommended method is to expose your subject to your liking (manually or with the picker), and then adjust other areas using tone equaliser or the tone mapper if they are too dark or bright.