Gordaen’s Blog

One extremely useful feature in any operating system is the ability to take a screenshot. You can use it to demonstrate what a window looks like, an error you are having, how many programs your computer can open before crapping out, or whatever else you think of. On a windows machine, you simply hit print screen (sometimes shortened to “prnt scr” or similar) to copy the whole window to your clipboard. Then you can paste it into whatever program, such as photoshop. You can do Alt + Print Screen to capture just the active window in the same manner. OSX has similar functions, though the keys aren’t as intuitive.

Note: I’m using OSX 10.4.7 at the moment, so the directions may be different for another version.

Pressing Command + Shift + 3 creates a full screenshot and places it as a PNG file on your desktop. PNG’s are lossless images, so the quality will be good. If you happen to have two monitors, the screen capture will produce two PNG’s (e.g. “Picture 3.png” and “Picture 3(2).png”).

If you want to capture just a particular region, press Command + Shift + 4 and your cursor will change. Drag to create a box to capture. If you need to make a particular program active, right click on it and then drag with the left mouse button.

Another useful thing to know is that OSX has a program called Grab. It can capture selections, windows, screens, and even do timed screen captures. After it has captured something, you can save it as a .tiff file. TIFF files are most commonly used for scanned images, but they are very flexible and widely supported, so you can manipulate the screen capture in most image editting programs.

I wish Grab had the ability to move selection boxes and to specify exact sizes to keep images uniform, but it is a decent tool for the basic uses of screen capturing and has more functionality than the Windows Print Screen feature. Just remember, you do have to open it before you can take advantage of the extra features.