adjust the exposure of several Images

Images of a photo series differ in exposure (bright, dark). Is there a possibility to adjust the exposure of several images in darktable? :nerd_face:

Can you be more precise here?
You want to apply the same adjustments to more images or to match the adjustments for some images to a certain one?
There are qays to achieve both …

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@Daniel_Catalina
I want to adjust the settings of several images (different exposures, dark, light) to a certain one. Similar to creating a panorama from several images :nerd_face:

For this case there is not an easy way to do it in any of the software I know. There are some threads here talking about fixing the exposure for time-lapses using various scripts.
This might point you to the right direction…

Maybe like this: activate module exposure, set to auto mode, then go to lighttable, copy history stack and paste it to another file or several other files.

I am not convinced that this will match the exposure as intended, but yes, it can be tried.
Most likely it will set the exposure where the exposure module thinks it should be, but not necessarily match it to a ‘master’ photo.

@betazoid @Daniel_Catalina

This does not match multiple images to one level.

I read on the Internet that Lightroom has such a function:
Select all of your photos, make sure your active photo is the “exposure” you want, and then go to Setting > “Match Total Exposures” (or type Alt+Shift+Command+M). This will intelligently and automatically alter the “exposures” on all of the photos so they “match” the active photo.

After a quick research for that “Match Total Exposures” I found this video saying that it only works with similar images.

Another info I found is that the actual opened photo is the reference for the other selected images.

I think this is a helpful feature in early phases of a photography workflow, in culling for example. You want to decide which images you keep or you want to give ratings for images. Comparing images with similar exposure is much easier.

Maybe an algorithm can look for min/max values in the histogram or peaks and adjust the exposure in the other pictures to match the reference values.

Or the guys that work on the timelapse have a working concept for this.

My panorama stitching software (Microsoft ICE) can adjust brightness and remove vignettes. As far as I know hugin does the same:
https://wiki.panotools.org/Hugin_Exposure_tab

Maybe the guys from hugin do have good ideas for this

@pphoto

My panorama stitching software (Microsoft ICE) can adjust brightness and remove vignettes. As far as I know hugin does the same:


That’s right.
It works in both programs (and other programs that can create panoramas).
Hugin even calls darktable and RawTherapy.
But I would like to use a corresponding function for RAW development of photo series in darktable.
(I don’t work with Lightroom.)

You can test the exposure module with ‘auto’ and change the last slider to what you want it to be, I think called ‘targeted exposure’ or something similar (I do not have darktable around now for a more precise description, sorry).
After that, just go in lighttable mode, copy this part of the history stack and apply it to a few other photos and see if it does what you want.

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It sounds like darktable’s exposure’s auto mode may be what you’re after.

In “automatic” mode darktable analyses the histogram of your image. You select a reference point within the histogram as a percentile and define a target level – darktable automatically calculates the exposure compensation that is needed to shift the selected position to that target value. The computed exposure compensation value is displayed in the module’s GUI for your information.

The “automatic” mode has a black level adjustment that works as in manual mode.

Automatic adjustment is only available for raw images. A typical use case is deflickering of time-lapse photographs. You apply an automatic exposure correction with the same set of parameters to all images of the series – differences in lighting get compensated so that the final video sequence does not show any flickering.

https://www.darktable.org/usermanual/en/modules.html#exposure

If I remember correctly, once you’ve done that for one image, you copy and paste in the history stack panel in lighttable mode from that image to the others.

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@Daniel_Catalina @DavidOliver

Thanks.
I already tried it, it didn’t work.
Now I will try it again with the detailed instructions, maybe it will work now.

@DavidOliver

I guess I’m too stupid for that.
Here are two images.
I took them especially so, that they have strong differences in exposure. The two images can be combined.
I can also upload them as DNG, do I have to pay attention?

Do the two raw files share the same crop? If not, I’m not sure the auto exposure method applies.

Feel free to upload the two raw files to a file-sharing service such as https://filebin.net/ so that I, or someone, can take a look. I think I’ve used darktable’s auto exposure across a few shots before.

@DavidOliver

Thanks for the tip.
Here are the two DNG images:
https://filebin.net/5qm9lc0l4pty7xhw

hugin can match the images.
The two images are in the panorama on the right side.

Hi, as far as i know is not possible in DT, the two images were taken with different camera settings and different crops.
The first one is 1/150 s and the second one 1/800 s.
If the crop were the same it will be possible to use the autoexposure functionality, if the camera settings were the same you could copy and paste DT’s history fron one image to the other.
Hugin works becouse knows the relationship between the two images and make some “magic”, but this is not the case in DT.
For panoramas is always a good practice shot in manual.

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IMHO it is possible.

  • adjust one, which is somehow in the middle, with exposure set to automatic (top of the module, not that thingie with colour picker)
  • go to lighttable and paste this setting to ALL photos of that series. (did this often on Panos)