Aperture 3.3 (or later) and iPhoto 9.3 (or later) use a new library format that lets you open both iPhoto and Aperture libraries using either application. This "unified" library format also allows you to merge multiple Aperture and iPhoto libraries together to create a single library with all your photos. You can then continue to use the library in both iPhoto and Aperture.
Merging libraries iPhoto libraries in Aperture
Before you start, you must have opened each iPhoto library you intend to merge at least once in iPhoto 9.3 or later.
To merge the libraries:
- Open Aperture 3.3 or later.
- Click the File menu and choose Switch to Library > Other/New. Use the library selector to choose one of the iPhoto libraries you'd like to merge.
- Choose File > Import > Library
- Select one of the remaining iPhoto libraries you wish to merge.
- Repeat steps 3-4 for each additional iPhoto library you wish to merge.
The library you started with in step 2 above includes content from all the merged libraries. The other libraries are still present (and useable) on your computer. Once you have confirmed that the unified library is working correctly, you may wish to remove the other libraries from your hard drive. It is a good idea to back up all your libraries before doing so.