Two copies of most files - fix?

Question

I'm new to Aperture and inadvertently imported two versions of the iPhoto files - causing almost all older photos to be double. I didn't notice this immediately, and managed to import additional new photos into both libraries. I currently have almost 12,000 photos, so correcting this manually isn't my first choice. Anyone have suggestions how I can automatically, or perhaps partly automated, deleted the duplicates without deleting the new photos added?

Answer 1

Did you import the duplicates all at once, or did you import, say pictures 1-100 once, an then later import pictures 1-100 again?
If it's the latter, you can make a smart album based on "import session". In that case, the import session will be the only difference between your two photos in the library. Make an album based on the import session of the first time you imported pictures 1-100. Once you make a smart album, you can select all and delete them.
If it's the former, it could be a little harder. If that's the case, can you make an album in which all photos are sets of duplicates? If so, I imagine that photos 1 and 2 are duplicates of each other, then 3 and 4 are duplicates of each other, etc.
Auto-stack all photos in your "duplicates" album such that Aperture makes stacks with photos that have the same exact time stamp (I.e., 0:00 apart from each other). Then close all stacks and then select all. *Closing all stacks is very important.* Selecting all when the stacks are closed will select only one photo from the stack. Once you have all those selected, delete all selected photos.
I've never tried any of this, so make sure you double-check each step of the way. If sounds like you have a backup of sorts, since you just imported the photos from iPhoto. Just remember, always have a backup, especially before doing something major to your library.
nathan