Batch processing in Darktable

blackstar

Senior Member
Hi,

I am a new user of Darktable and I am learning batch processing in Darktable (don't have Lightroom or Photoshop) for "Startax" multiple night-star shots into a startrail image. So far, one critical issue hit the work: I process the first photo to light up only the foreground image by using a mask in Exposure module. Then I create a style for this process. When the style put to work on the rest of the batch, the exposure process is applied to the whole image without masking out the dark sky! (every one of the rest of the batch) Is it the fact that Darktable does not save all the detailed mask usages in style to be used for batch processing? Kind of cheap crap, if it is true. But I hope I am missing something critical and important here. Did anyone get any idea or corrections on my part? Thanks for help.
 

blackstar

Senior Member
Pic 1: original photo #1
DPM-star-trails-001-1600px-s.jpg

pic 2: photo #1 after DT processing
DPM-star-trails-001-1600px-DT-s.jpg

pic 3: photo #4 after style applied
DPM-star-trails-004-1600px-DT-s.jpg
 

Needa

Senior Member
Challenge Team
How was the mask created? Have you instead of creating a style just copied and pasted the history stack to each image? Once the original image is edited it can be done by coping the history stack then selecting a single or multiple images and pasting that stack to the images. This can be done in the lighttable mode.
 

blackstar

Senior Member
Thanks, Needa.

The mask was created by using the "path" tool to lighten up the foreground (see pic.2). I think it is the same as either copy-paste history stack or apply style for the batch processing. I could see the style created has the same history stack with the "exposure" module as in the copy-paste section. These two ways (sections) are all to be done in LT only. So still ???

I reckon I could lighten up the foreground in the final startrail image without doing it in every individual photo. But still, sometimes it needs to batch process each image before Startax, e.g., bring out all (or more) stars in the sky. So the batch processing feature in DT needs to be fully functional.
 

Needa

Senior Member
Challenge Team
_71D2968.jpg

Original

_71D2968_path.jpg

One stop path added to upper dark area.

Using different photo for output.

_71D2969_style.jpg

Created style no change.

_71D2969_stack.jpg

Using stack

As you can see it is working for me using the copy stack method and not the style. Running darktable 3.0.2.
 

blackstar

Senior Member
Hi, Needa. Thanks for replying.

Sorry, I don't understand what you mean by "one stop pass" added to... Did you draw a mask to do it? Which module did you use?

Ok, you created the style, but did you apply it to the other photo? You have to double click the style (name) to apply it.
 

Needa

Senior Member
Challenge Team
Compare the first and second photo and notice the change in the black area. I used the path to to create the mask and use exposure to lighten it for the change. I then created a style from image #2 then applied it to a different photo (#3). I then copied the history stack from image #2 and applied to #4. Image #4 clearly show the mask was applied where #3 does not.

Hope that helps.
 

blackstar

Senior Member
Ok, I did copy-paste history stack on photo #4 and it worked! Evidently, there seems some glitches with the "style" section and it's not fully functional.

Photo #4 after C-P history stack:
DPM-star-trails-004-1600px-DT-batch-s.jpg
 

hark

Administrator
Staff member
Super Mod
Contributor
I don't use Darktable but have to ask...what caused these light-colored splotches in the sky? Were they in the original images, or did they appear after applying Darktable processing? :confused:

DPM-star-trails-001-1600px-s.jpg
 

blackstar

Senior Member
Hi Cindy,

Yes, they are in the original images. I guess they are part of the sky color in that region (the site images were taken). If you look at pic 3 (sky lightened up) in my post, those parts of the sky look a little like the MW at the right side that glows just not as much. These images (90) are downloaded from an online tutorial that provides the sample images for the practice of creating startrail image with Startax. Pretty sure the splotches are in the original images and not created from using DT. The tutorial lady used LR to light paint the foreground from one individual image and layer-stack with the startrail image for the final version. I don't have LR, so tried DT to lighten up the foreground (not as good as using light painting though).
 

hark

Administrator
Staff member
Super Mod
Contributor
Hi Cindy,

Yes, they are in the original images. I guess they are part of the sky color in that region (the site images were taken). If you look at pic 3 (sky lightened up) in my post, those parts of the sky look a little like the MW at the right side that glows just not as much. These images (90) are downloaded from an online tutorial that provides the sample images for the practice of creating startrail image with Startax. Pretty sure the splotches are in the original images and not created from using DT. The tutorial lady used LR to light paint the foreground from one individual image and layer-stack with the startrail image for the final version. I don't have LR, so tried DT to lighten up the foreground (not as good as using light painting though).

That's okay. I've just never seen any Milky Way images with a sky looking like that. :)
 
Top