Many of us already know of the ancient keyboard shortcut ⌘-Shift-3 to capture your screen to a picture file. It’s been around since System 7, and it’s still with us. We’ve made some significant progress over the years. The ⌘-Shift-3 trick captures a full-resolution image of your screen and places the PNG file on your desktop. From there, you can open and edit the image as you see fit.
It’s rare, though, to need a full screenshot. For these situations, I use ⌘-Shift-4, which turns the mouse pointer to a crosshairs to allow for precision selection of a portion of your screen. I often find myself writing documentation for company procedures and posting the information to our company wiki (powered by Mac OS X Server), and taking screenshots is a very effective way to visually convey knowledge. I love saving the step of cropping in Preview.
⌘-Shift-4 is more powerful than it might seem, though. You can press the key combination and then press the space bar. The mouse pointer changes to a camera, and individual windows and menus are highlighted when you hover over them. Clicking the mouse yields a screen shot of just that window or menu.
The Grab application, found in your Applications folder, allows you to take a timed screenshot by selecting “Timed Screen” from the Capture menu.
These tips can be taken a step further by taking the screenshot and automatically copying it to your clipboard for pasting wherever you’d like. Simple add the Control key to the shortcuts above and you can paste the screenshot directly into any application.
Snow Leopard takes this concept a bit further by allowing you to record video of your actions on screen in QuickTime Player. It records your voice and your screen by default, and it’s my new favorite tool for producing training materials.