Want to quickly and easily locate all the photos in a project that you’ve spent some time adjusting? Aperture makes it easy, by allowing you to search for photos based on the adjustments that have been applied.
Your photos are automatically filtered so that only the images you’ve adjusted appear in the project or album. To see all images again, click the small x in the Browser search field to clear the query.
You can use this same technique on your entire Aperture library to see all the photos you’ve adjusted in all projects at once. Just click All Photos near the top of the Projects pane, and then filter the images in the Browser using the Query HUD, following the steps shown here.