How do I create a new Aperture library on my Mac?

I take a lot of photos. So many that Aperture is starting to bog down. I was talking with a fellow photographer and he said that he splits his Aperture library every six months. Sounds like a good idea. How do I create a new Aperture library or, better, move a project into a new library?

I’m a big fan of Aperture, but I have definitely found that it works a lot better with a few thousand photos than it does with ten thousand or more. Yes, I also take a lot of pictures! I don’t split things every six months, however, but I do create a new Aperture library every year, typically after I’ve imported a project or two in early January and realized that I haven’t split it off yet.
If you’re relatively new to Aperture, a “library” is a collection of “projects”, each of which can be comprised of one or more “events” which themselves are collections of photographs. So when I went to the 2012 Consumer Electronics Show, for example, I kept all the photos from the show in the same project, even though they were taken over the course of four days.
That being explained, there are two ways you can create a new library in the program. The first is to simply create a new library…

Creating a New Aperture Library

There are three steps to creating a new library, starting with choosing “Other/New” from the “Switch to Library” option on the “File” menu:

Aperture asks what library you want to use:

You need to click on the “Create New” button on the bottom, at which point the program asks you to name your new Aperture Library:

You’ll notice that I’ve stayed consistent with my naming scheme of “Aperture YEAR” by naming the new one “Aperture 2012”. I recommend keeping these libraries in the “Pictures” directory, but you can put it wherever you want, of course.

Exporting Projects as a New Aperture Library

If you’ve already imported one or more collections of photos into Aperture, however, creating a new library isn’t helpful because it’s tedious and a hassle to export projects and then import them into the new library.
Instead, select all the project or projectss you want to move, then Cmd-Click on any one of them:

As you can see, “Export as New Project” is the option to select. Pick it, then name your new Aperture library, perhaps “Aperture 2012” as I did. It’ll export the projects and create the new library which you can then easily switch to and proceed.
Hope that helps you get the most out of Aperture!