Another awesome shortcut, it's called the lights out, lights out mode, and that simply you press the L key. Pressing the L key will simply shut the lights around the image off. So you can just look at the image, press it again, makes it darker, which is a really, really awesome tool to use. If you want to kind of sit back and enjoy your work and maybe see what else you can do to it. You don't have to look at all the other mess and on the screen. You simply press the L key and you can have the lights out.

Very, very cool shortcut to use. I use this all the time.