Aperture 1: Actions apply to all images in the Viewer

When you have multiple images in the Viewer, the following will be true:

Adjustments include anything that appears in the Adjustments Inspector, such as Straighten, Levels, Sharpen, and so forth. Actions include application of a rating or keyword, stamping of metadata, and similar.

When you want to isolate only the selected image in the Viewer for an action, use the Toggle Primary Only button in the Control bar (also available via the keyboard shortcut "S" and via Edit > Primary Only).

Which image is the "Primary?"
When multiple images are in the Viewer in Multi mode, each image will have a white outline, because each is part of the multi-image selection that placed them all in the Viewer. One of them will have a thicker white outline, signifying that is the primary.
Published Date: Oct 10, 2016