Making Screen Capture Images with a Mac

Making screen captures is quick and easy, and you can use the resulting images in lots of different ways.  You can illustrate something to your students in a lecture or discussion, use them for computer-related tutorials, and use them in your research.

On a Mac, the ability to create a screen capture is built into the operating system via a command in the Finder.  This means that at any time, you can make a capture of your entire screen, of a portion of your screen, or of a specific window on your computer.  To do this:

  • Hold down command-shift-3 to make a capture of your entire screen
  • Command-shift-4 will give you a crosshair you can use to select part of your screen
  • To capture a single application window, press command-shift-4, then hit the spacebar when you get the crosshair, then click on the window.

Doing any of these three things will save the image of your screenshot as a .png file on your desktop. You can also change where the screenshots are saved, and as what format, if you’re willing to mess around in Terminal.  Easy enough, right?

A Caveat to Screen Captures of DVDs

However, if you’re trying to create a screenshot of a movie on a DVD, your image might end up looking like this:

Blank screen

Uh oh — this image from 2001: A Space Odyssey was not supposed to look like this …

What gives? I thought that 2001: A Space Odyssey was a film known for its spectacular visuals — I don’t remember it looking like that!

As it turns out, Apple has built in a block to creating screen captures of images from DVD Player into the Mac OS, presumably for copyright reasons.  Any screen capture made with the DVD Player application will end up looking like the above image.

Using VLC for Video Screen Captures

This VLC screenshot is much better than the one I took using the Finder and DVD player above!

This VLC screenshot is much better than the one I took using the Finder and DVD Player above!

If you do want to capture an image from a film, you can still do so without resorting to what’s available via poor-quality YouTube clips.  I use an application called VLC to make screen captures of a DVD (I also use it as a video player, because it plays all different kinds of digital video files).

VLC has a built-in screen capture tool, also, so you don’t have to use the Finder’s keystrokes to do it. The advantages of doing it from within VLC is that it automatically crops the saved screenshot to the proper size, so you don’t have to spend extra time doing it yourself.  You can also easily choose where you want your screenshots saved, so your desktop doesn’t become cluttered with image files.

Some Additional Tips for Using VLC

A couple of brief tips on using VLC to capture DVD video images:

  • Open your disc with VLC, then go to the Video menu and select “snapshot.” Or hold down “command-option-s” and that should make a snapshot.
  • Pausing the DVD before taking the screenshot is a good idea — this will result in you capturing exactly the image that you think you are capturing.
  • The size of the VLC window of your movie doesn’t matter — VLC will always create images of the same size and same resolution.  If you use the Finder’s screen capture tool, this is not the case, and if you create an image when the window is quite small, it will be of lower quality than an image created with a larger window.
About Kim Mann

Kim Mann is the editor and a writer for the Academic Technology Blog. She earned her BA in English from the University of Minnesota in 2003 and her MA in American Studies from William & Mary in 2009, and her PhD in American Studies at the College in 2014. Her research is on technology, the interface, and the body in mid-twentieth century science fiction.