The following tip comes from the Apple Pro Training Series: Aperture 2 book published by Peachpit Press.

Once the displays are attached, you’re ready to configure Aperture for multi-screen viewing. When two displays are connected to your Mac, Aperture considers the main display—the one with the menu bar—to be the primary Viewer. The other display is the secondary Viewer. By default, the primary Viewer displays the Aperture application.

Let’s specify the function of the secondary Viewer.

1 From the control bar, click to open the Viewer Mode pop-up menu.



If you have two displays connected, then you’ll see separate sections for each display.

2 Choose Mirror from the Secondary Viewer Mode pop-up menu.

3 In the Browser, select any three images. You should see all three images appear on both displays. The second display is showing an exact mirror of the Viewer of the first display. Obviously, the difference is that the second display shows the selection full-screen, with no interface elements.


4 Choose Alternate from the Viewer Mode pop-up menu.

Your primary Viewer should still show all three selected images, but the secondary Viewer should change to show only the primary selection.

5 Use the Left and Right Arrow keys to navigate through the images in the Browser. The second display will update to show only the current primary selection.

6 Choose Span from the Viewer Mode pop-up menu.
Some of your selected images should move to the second display, while the rest of the images in the selection remain on the main display. Span mode spreads the selection across both displays, so your images can be viewed at a larger size. How Aperture chooses to divide them up will depend on the size of your Viewer and the size of your displays.

Tip
If you want to use your second display for something other than Aperture, you can choose Desktop from the Viewer Mode pop-up menu. This reveals your Mac desktop and frees up the display to show the Finder or another application. If you want to completely eliminate the use of the second display, choose Blank from the Viewer Mode pop-up menu.