Adobe Lightroom (excuse me, “Adobe Photoshop Lightroom”) has some features I’d really like to have in Aperture, such as the Recovery slider, which lets me do highlight recovery without affecting the midtones and shadows in an image, and the Vibrancy slider which provides a great way to boost saturation while protecting skin tones.
That said, I still greatly prefer Aperture for its overall lack of modality, and for its far superior organizational tools. Lightroom’s Collections don’t come close to Aperture’s Project structure in terms of creating robust, flexible organizational schemes.
Nevertheless, I still find that Folders confuse a lot of Aperture users because people don’t really understand “where they go.” A folder is nothing more than an organizational structure that you can use to contain other elements in your library. Folders can go inside of projects, or outside projects, at the Library level. The idea with folders is simply to provide a way for you to reduce the number of entries in the Project pane, so that you can see more of them on-screen at once, and to ease navigation.
For example, last year I went to Death Valley and did some shooting. Upon my return, I created a “Death Valley 4-2006″ project and loaded my images into it. Last week, I went back to Death Valley and so came home and created a “Death Valley 3-2007″ project and loaded my new images into that. Next, I created a Death Valley folder and put both projects inside. I now have one Death Valley entry in my library - a Folder - that can contain every Death Valley project I ever shoot. (To create a folder at the Library level, you must click on Library at the top of the Projects pane, before you choose File > New Folder.)
In one of my projects, I created several different web galleries. I can create a folder inside that project to contain all of my web galleries, just to keep the project itself better-organized.
Finally, thanks to Smart Albums, I can automatically culls the best images from both projects, allowing me to keep a running tally of all of the selects from each project. I place a Smart Album configured to cull 3-star images, and place that in the Folder. Note that the Folder automatically constrains the reach of that Smart Album to just the projects contained within the folder, making it simple to create Smart Albums that search only a specific selection of projects.
So, everything you need to know about Folders: they can go inside or outside of Projects; they exist simply to help you organize other elements in your Library; they allow you to constrain the effects of Smart Albums to a select group of Projects.
Still want that Recovery slider, though…