The question is in the title. This would be very useful in many circumstances, for example to try to match multiple frames from the same scene against a fixed reference.
There are two options that get close, but they fall short of one of the requisites:
Taking a snapshot of the reference image and showing it together with the current image. This would be perfect, but it interferes with editing, as all click-related interactions in the center-view (e.g., color pickers, crop, etc) stop working when the snapshot is overlayed.
Second darkroom image view, which has the problem that it can only show the image currently being edited.
The best workaround that I could find is to open the reference image in a second instance of darktable with a different configdir (with sidecar files disabled) and in-memory database. This has the advantage that I can also compare histograms, but it’s very wasteful and not very practical.
A less wasteful (but also convoluted) option is to take a screenshot of the reference and then open it in a separate image viewer.
Is there some option that I am missing, or is there another workaround that folks are using to achieve the same result?
There’s also the “second darkroom window” button on the bottom panel.
Though I can’t seem to get this to work in Windows, it creates the window but it’s just a small window that can’t be brought to the foreground and has no content.
Ok it does work but I have to go to the task bar, hover over the darktable icon to bring up both preview windows, right click on the new window, and select “Move” to be able to do anything with it.
Thanks @wpferguson, that seems very useful but I am not talking just about color grading. For example, I want to tone-map two B&W images taken in slightly different light conditions to achieve a similar result.
Exposure has the same feature too…you can sample a reference image and then apply a correction to subsequent images…doesn’t help with your side to side issue but it might be a tool that works for your BW images…
I think you can take a snapshot of one image and then turn it on in the other image. I think that’s about as close as you’re going to get right now.
This is the solution I sometimes use. I’m on Windows, so I use the Screen Snip option from the taskbar to quickly take a screenshot.
Like you, I was missing an option to have a side-by-side view of two images in the darkroom. I actually requested the side-by-side snapshot feature, and I was delighted how quickly it was implemented after the feature request. However, the developer did acknowledge that it would have certain limitations due to the way the pixelpipe works.
I’ve always thought the “Display 2nd Darkroom Window” option would be ideal for displaying a reference image. I’m actually not sure what it’s useful for in its current state.
The ability to choose either a snapshot or totally different image in this window would be useful.
Having a close-up view on some details while having a fully fit view in the main windows. Useful to watch how a contrast local do actually works on some details or when applying D&S.
