As Tom Giannattasio explains in an essay written for Smashing Magazine, "design is a fluid and shifting process in which layers are constantly modified and tweaked. As complexity builds, so does the need for preserving data in a flexible way. Learning non-destructive editing techniques helps you produce documents that bend along with your creativity. Photoshop Masks are the cornerstone of this process."
In order to complete this badge, you will need to locate a copy of Adobe Photoshop. You can download a thirty-day trial version from Adobe, and you can also access Photoshop on any of the lab computers.