Any way to remove all photos that are in one album but NOT in another album?

[james_dh]

I'm trying to do some cleanup of 1000's of photos that I no longer need. Basically I copied the same lengthy set of timelapse photos to two seperate albums, one that is an "All" album, and the other that is "Curated". What I had been doing was deleting unwanted photos from the "Curated" album, but kept them in the "All" album in case I made need them again. However, now I've got 1000's of photos that I know I won't need and cannot find any easy way of removing them permanently from my library without also deleting the photos that are in my "Curated" album. 

There does not appear to be any way to do this. That seems crazy for what is essentially a photo management/organization tool. The only possible way I can think of is to export all of the raw images from my Curated album, permanently delete the All album (which will also delete all the photos in the Curated album), and then reimport all the exported images back into the Curated album. But that's literally 10's of 1000's of photos totaling 100's of GB's that would need to be resynced to the cloud. 

I find it hard to believe their UI is this limited. Am I insane?

[Rikk Flohr: Photography]

This looks like it works:

1. Go to "All" Album
2. Select all
3. Apply Keyword "To Delete"
4. Go to "Curated" Album 
5. Select All
6. Remove Keyword "To Delete" by clicking on it in the Tag panel
7. Go back to "All"
8. Search for "Keyword: To Delete"
9. Select All
10. Delete
    
    Unless I am misunderstanding your need...

[james_dh]

That did actually do the trick. Thank you Rikk!

[james_dh]

Unfortunately after doing this, I'm in a perpetual "Syncing" state, w/ Lightroom consuming 200%+ of my CPU on a MacBook Pro M1 Max, and with zero network traffic. I don't know what it is trying to sync since I only deleted files and didn't change any, but it doesn't seem to be actually making any progress given the constantly pegged CPU cores and complete lack of network traffic. I've tried restarting it twice now, but it just goes straight back into the same "Syncing Items" state. It's not even able to tell me how many items are syncing which I've usually seen in the past.