In my last entry, I extolled the virtues of Aperture’s Compare feature, which makes it simple to compare a group of images in a project to find the one you like best. As I stated then, I’ve been very surprised to find that many people don’t know about this great feature. A few people posted comments saying that the feature was news to them, which made me start thinking that maybe I’ve also been incorrectly assuming that people are wantonly using Aperture’s Stack Mode, a similar tool for comparing images in a stack.

The first image in a stack is, of course, the pick of the stack. Usually after you create a stack, you want to compare all of the images to find the best one. You can do this manually by shuffling the images in the stack around with the mouse, or by using the Promote and Demote commands (Command-] and Command-[) or by using the Pick command (Command-\).

But, Aperture provides a special Stack mode that offers features very similar to the Compare mode that we looked at before. To enter stack mode, select any image in a stack and press Option-T, or choose Stack from the Viewer Mode popup menu on the left side of the Control Bar.

The current Pick image in your stack will shift to the left in the Viewer, and will be bordered by an orange rectangle. The next image in your stack will appear in the compare position, to the right. This is just like the Compare mode that we looked at earlier.

If you like the right-hand image more than the current pick, press Command-\ to make that image the new pick. The old pick image will fall into second position in the stack, and the next image after the one you just selected iwll move intot he compare position.

If you don’t like the current selection more than the current pick, press the right arrow key to go to the next image.

When you get to the end of the stack, pressing right arrow won’t do anything, because there’re no more images to select. But, if you press the Down arrow, Aperture will automatically close the stack, open the next stack in your project, and throw it into compare mode. In this way, you can quickly navigate through all the stacks in your project, comparing and selecting, and all without ever touching the mouse.

Another handy side effect of Stack mode is that, as you continue to select picks until you find the one you want, the images in your stack will automatically fall into order from pick to second best, to third best, and so on, meaning your choicest alternates will automatically filter to the front of the stack.

When you’re ready to leave Stack mode, press Option-U or choose Multi from the Viewer Mode popup menu on the Control Bar. Note that the shortcuts for changing the viewer mode are simply option plus the second letter of the name of the mode.

Finally, two other Stack shortcuts: Option-; will close all currently opened stacks, while Option-’ will open all of the stacks in your project.