JPEG Thumbnail in culling layout not working with 2 images


following an advice from @s7habo in one of his videos, I am trying to compare an edited image with its JPEG using culling mode. It seems that the functionality does not work when the selected number of images in culling layout is 2:

When selecting more than 2 images in culling layout it seems to work:

I was reading the darktable manual and some interesting posts about thumbnails but I cannot say if it’s a bug or a feature. Has someone an idea?

I’m using version 3.9.0+1744~gebe766dba current OSX Build - #505 by MStraeten

Could someone confirm that this is a bug? I can then try to report a bug in github. Thanks! :slight_smile:

I was doing some tests and the issue seems to be related with the size of the thumbnails. I get it working as expected (JPEGs are shown) when I make the darktable window smaller, and hence the thumbnails also smaller.

Those are my settings:

Am I doing something wrong?

Sorry, I’ve missed your msg… For me that looks like a bug. Can you open an issue on github and assign it to me ? I’ll try to look at it (but don’t don’t expect too much until end of august ;))
Thanks !

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I may be missing the point here. I’m relatively new to dt myself. But is the problem in the first screenshot that the raw is displaying with dull colors, ie. a default processed view as opposed to the embedded jpg thumbnail?
I’ve found this with my Sony files if I make the lighttable view any bigger than 2 images. Turns out it’s because the sony files only have a low-res thumbnail in them.
Sorry I’m on the wrong track!
Edit: on rereading the post, I think maybe the problem is actually that dt is showing an un-edited raw as opposed to the user-adjusted version. I’m stating the obvious I guess…

Hi @AlicVB ,

finally I create the issue on github, but don’t know how to assign it to you.

Thanks for your work!

@123sg it turns out that you are completely right. I watched the video of @s7habo again and tested it with the same RAW image that he was using and it works then.

I use also a Sony camera and it seems to be the reason this functionality is not working with its RAW files.

Do you know if it’s possible to make the embedded JPEGs bigger?

FYI @hannoschwalm @Pascal_Obry : I think the issue on github can be closed, because the culprit seems to be the camera, not darktable :slight_smile:

I’ve investigated by myself and it seems not possible to make the embedded JPEG bigger. The only solution would be to shoot RAW+JPEG

That was my conclusion too! Shooting Raw+jpg does have the disadvantage that when raw+jpg pairs are shown grouped in DT (ie one thumbnail for the pair), it is the raw that is shown in the culling and sticky preview layouts. There is a lua script to change this though which I haven.t got round to trying yet… mentioned in this thread Ordering of RAW+JPG pairs - #2 by wpferguson

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