Evelyn,

I’m not quite sure I understand what you want to achieve.

Starting a new Aperture library is easy (just go to to the menu File > Switch to Library > Other/New…) to make a new one—and what’s great about that too is you don’t have to throw away your existing library. You can have multiple Aperture libraries, and switch between them using that same menu.

You asked how to find images that you’ve edited in Aperture… do you mean ones that you’ve imported from iPhoto, edited, and now want to bring those edits to the new Library? Or do you mean photos you’ve imported since then, and now want to move into a new library?

Moving photos is easy. You can select any Project(s) or Album(s) as a Library, then merge that library with another one. In fact, save yourself a step, and just put all the projects you want to save into a Folder in Aperture, then select that Folder and go to the menu File > Export > Folder as New Library…, and save that wherever you like. Then switch to that new Library using the Switch to Library menu, and you’ll be working just with those exported photos.

Does that make sense? Is that what you wanted to achieve?

Evelyn,

So sorry for the delayed reply. I missed your response somehow.

Aperture’s awesome search tools to the rescue. You can search in Aperture by just about anything—including whether adjustments have been applied or not.

In fact that was such a pertinent question that I just turned it into a tip on the front page! Finding Adjusted Images in Aperture 3.

That will allow you to find all your adjusted images easily. Just run that search on the entire library. From there, I’d select all the adjusted images and move them into a new Project, then export that Project (as a Library) from the current Library. You can then discard the old Library, and just run with the new one, and import anything else you like into that.

If any of that doesn’t makes sense, let me know and I can explain in more detail.

Good luck,
-Joseph @ApertureExpert