Apple Aperture 2 - Manual (Page 203)

Chapter 6 Displaying Images in the Viewer 203
II
Generating Previews for Projects You Intend to Keep Offline
A JPEG preview is displayed when a referenced image’s master is offline or cannot be
found. This makes previews a great way of maintaining high picture quality while
conserving the disk space that masters (especially RAW files) require.
To use previews for offline referenced images:
1 Make sure the external hard drive containing the referenced masters you want to keep
offline is connected to your computer.
If the masters you want to keep offline are currently stored on your computer, you
must convert the images to referenced images and move the masters to an external
hard disk. You can do this by selecting the project containing the images whose
masters you want to keep offline, choosing File > Relocate Masters for Project, selecting
an external hard disk location for the masters, and then clicking Relocate Masters.
2 Control-click the project containing the images whose masters you want to keep
offline, then choose Update Previews from the shortcut menu.
3 When the previews are built (you can tell by choosing Window > Show Activity), you can
disconnect the hard disk containing the masters.
Even though the masters are offline, you can browse, search, and assign metadata to
preview images. You can even use the Loupe to zoom in on preview images, because
they are high-quality JPEG files.
Generating Previews for Images Based on Rating
Another way to use previews is to create a search that displays only low-rated images.
You can then build previews just for those images, and take their masters offline (for
example, burn them to a DVD). That way you still have good-quality images for all of
your photos, without using a lot of disk space.
You can also create a search that displays only highly rated images, and then build
previews for those images only. This is a useful alternative for workflows where the
default thumbnail resolution is sufficient for low-rated images.
Generating Previews for New or Active Projects
Because previews are used by the iLife and iWork media browsers, as well as by the
Mac OS X screen saver, you can use previews as a way to distribute your Aperture
pictures in movies, on the web, on DVDs, in slideshows, and in podcasts. You can also
download your Aperture pictures to your iPod, import them into iPhoto, or use them to
create Pages documents.