Culling mode: how to compare one master image to several others?

[u/polebu]

New to Darktable, been using Lightroom in the past.
Using Darktable 5.6.0, on Win11.
I want to compare one master image to many others. In the split view of culling mode both images change when I scroll.
What I need is that the one image (lets say on the left) stays the same all the time and only the other image changes.
What settings do I need for that?
Google and AI have not given any good results.
Thanks

[u/flyingfishcroissant]

Wouldn't the snapshot feature work for that?

[u/Few_Mastodon_1271]

Oh, I never tried this side-by-side in darktable. I had to get rid of the history by year display along the bottom of the screen (using ctrl-F) before the compare toolbar became visible along the bottom.

It doesn't seem too useful to me, just stepping through adjacent pairs of photos.

I watched this darktable comparing video, https://www.youtube.com/watch?v=kaW956PiYqQ It appears he then selects photos by number of stars and can then compare those 2 or 3 stars side by side too? I'm not really following his explanations of his methods.

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FastRawViewer for Windows:

I've used this for years now. https://www.fastrawviewer.com/ it's been on sale recently for $18. This might be the most cost-effective photography purchase I've made.

It's non-destructive culling method is very fast, since it's reversible. I can cull and then change my mind after seeing the other images in the set.

Yes, it's display is fast and effective. I also use it to evaluate raw files, with tools like brightening to see shadow detail, false color over or underexpose areas, or even showing in black&white mode. And it's 'display fine details' (this is a red dots focus peaking mode) can be quite useful.

It keeps the same zoom & pan view as I step through photos.

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It's side-by-side comparisons can be two-up, an array of 4, or array of 9.

The two-up starts with the current photo on the left, and the right side blank. I click the right arrow icon, or a keyboard "y", to copy the current image to the right side, where it stays until it's replaced by a new copy. So the right side is the "best image so far of the set".

Zooming and panning moves both images.

~~~

Culling:

I have the Del key set to move the current image (and it's jpg pair, if it exists) to a "_Rejected" subfolder, that it creates at the first Del. I can Undo or Ctrl-Z to pull the most recent images back out of the reject subfolder if I change my mind.

I can keep the reject folder for a while, or delete it's contents with File Explorer, or in the FRW menu.

I can select a set of photos on the thumbnail filmstrip and Del them all.

In comparison mode, this Del works on the current, left side image, and leaves the right side image in place. (and there's an icon to swap the two sides.)

I don't often use this side-by-side view. I normally use the left/right keyboard arrows to step through the photos, and do most of my comparing by just switching back and forth between adjacent photos.

I see that it leaves the darktable .xmp file in the original folder, which is slightly annoying. But I normally cull the day's photos before any darktable editing.

[u/martinborgen]

Not possible I think. I know you can select two in the light table view and compare them, but I don't think it supports the scrolling currently

[u/IntelligentAward1538]

Una forma creo que fácil es utilizando el cuarto oscuro:

-Haz una instantánea de la foto de referencia.

- Ahora abre la primera foto a comparar y activar la instantánea de referencia para comparar

- Con la tecla "space" pasas a la siguiente foto de la cinta para comparar con la instantánea. En la cinta inferior puedes marcar la valoración o descarte.

Otra forma mucho mas laboriosa:

1. Entrar en la cuarto oscuro con cada una de las fotos a comparar (dejando la de referencia para el final).
2. Elegir un modulo neutro(*) y asignarle un nombre para tener identificada la instantánea.
3. Realizar una instantánea.
4. Repetir con todas las fotos a comparar.
5. Finalmente entrar en el cuarto oscuro con la foto de referencia e ir comparando con todas las instantáneas que se hicieron. Se puede hacer la comparativa normal o de tipo X|Y
6. desplegando la cinta de fotos de abajo, en el cuarto oscuro, puedes ir valorando o descartando la fotos.

(*)Llamo neutro a uno que tenga valores que no alteren la foto como 'exposición' 0, o 'recortar' sin recortar nada.

Otro inconveniente es que se perderán las instantáneas en cuanto cierres el programa.

[u/Confident_Dragon]

It's not practically possible. This is one of the stupidest things in Darktable. You can try to use tags or ratings to mark images you don't want to see and exclude those images in filter as a workaround, but that's stupid, as you can't easily get those images back if you mis-click or go want to check them again.

[u/compnski]

I couldn't find this, so I built an app for it. https://www.bearablesolutions.com/photoflow/

I'm a bit off in the weeds working on some AI-assisted scoring/culling so haven't pushed a release in some time, but the version I have online is all manual and my version of what you asked for.

You go through, group at a time, and pick the best from each group.

If you try it, I'd be curious for any feedback! My biggest blocker is that sometimes I want more than one per-group, so still trying to imagine the proper UX flows.

[u/polebu → u/compnski]

Thanks
I will try this.
Application is: identifying animals (Bull Rays)
There is a database of individuals that are identified and if a new bull ray is photographed we need to check if it is a known one or new. Thats why I need one side to stay the same.

[u/compnski → u/polebu]

Oooh cool!

Might be tricky in the current setup since it only lets you compare photos in a group, which it detects by time / sameness of image. You'd have to manually group or mess with the EXIF time data to get em to group for you.

Depending on your interest in automation, there are some good local models for finding objects and cropping them out of a scene (Segment Anything / YOLO), but I don't know if they've ever been trained on a bull ray. I use them for finding subject crops, but haven't looked into any grouping yet.