If you were used to inverting the colors on your Mac with a Control-Command-Option-8, you might have noticed that this has changed in OS X Mountain Lion. The older keyboard shortcut doesn’t work any more, and has been replaced with the less simple Command-Option-F5 shortcut to bring up an Accessibility Options dialog box. You have to then manually click the checkbox next to Invert Display Colors.
Here’s how to get the old shortcut back, for a quick invert.
Launch System Preferences from your Apple menu, dock, or Applications folder and click on the Keyboard icon. Once in the preference pane, click on the Keyboard Shortcuts tab, then click on Accessibility on the left. Scroll down a bit to the Invert Colors checkbox and click on it. Now you’ll be able to invert the color of your Mac display with one quick keyboard shortcut, rather than having to bring up the Accessibility dialog box, take your hands off the keyboard, and use a mouse.
Faster access to these features is key to those who need this as an accessibility feature, due to their own individual visual impairment. It’s even useful for those without an impairment to use a Mac in dim light.
Via: OS X Daily