You can invert colors on your computer screen on Mac, follow the simple steps below

Keyboard Shortcut Method

With one hand, hold down the three keys at the bottom left of the keyboard:

• “Control, “Alt/Option”, and the Command Key (right next to the Alt/Option key).

With your other hand, press “8” in the row of numbers above the letters. Note that this will not work if you use the number pad on the right.

Enjoy your new colors.

Change the colors back. When it comes time to change it back (because, unfortunately, it’s unlikely that everyone will love their “negative”-looking computer), just press “Control”, “Alt/Option”, Command, and “8” again, and watch your computer flicker back to color.

System Preferences Method

Go to System Preferences. System Preferences is the icon that appears as a white light switch with an apple on it in OS X 10.3 and earlier, and as a silver gear icon in OS X 10.4 and later.

Click the Universal Access button. This button is the last icon on the row marked System.

Under Display, click the radio button White on Black.

Sit back and enjoy your new, cool computer.

Reconsider if you must. To change back, go to System Preferences again and click the radio button Black on White.

Note

• If you share a computer, make sure everyone else who uses it knows what you’re planning to do. You don’t want to scare anyone.
• Before doing this, consider what your favorite webpages look like. If most of them are white or gray with black writing, you’re okay because it will just show up as a black background with white text. But combinations like these will most likely show up all white: blue on black, black on blue, purple on blue, etc. And color combinations like white on gray, gray on white, white on yellow, etc, will look all black.
• Online Games will probably look weird with the colors inverted.
• You may notice the cursor flickers a bit every once in a while.
• When inverting the colors, or changing them back, the display will flicker a little bit. Don’t be alarmed.
• Pictures will now look negative. For example, if you have a picture on your desktop of a black horse with a white mark on his face, and then you invert the colors, he will appear ghostly white with a black smudge on his face.
• Inverting colors helps your eyes by preventing them from hurting and deteriorating, because it decreases the total amount of light emitted by your screen by making it predominantly black.
• Inverting colors can help visually disabled people more easily see their screens.
• Inverting colors reduces your power consumption, which is a plus for the environment, and extends your battery life for the same reason that it helps your eyes.
• You may notice that sometimes, when you do this, everything will end up black and white, but other times the colors will actually reverse (ex., blue will turn orange-brown).
• If anything seems messed up when you change the colors back (see warnings for some known mess-ups), just restart the computer to set everything right.
• This also works if you use the Apple, Alt/Option, and Control keys at the right of the space bar.
• One cool thing to try after doing this is to launch your screen saver (if you use one).
• Sometimes when taking a picture in Photo Booth and want a dark scene, you can ‘disable’ Photo Booth’s flash by using the keyboard shortcut above. This way, when taking a picture, the screen will turn black instead of white right before the picture is taken since colours are inverted.
• It’s best not to do this on a public computer. Other people may not know how to change it back.
• It is not recommended to edit a photo or put together a movie when your monitor’s colors are inverted. When you set the colors right, your final product may look really weird.
• After you do this, when you move your cursor over an icon on the dock, on some older computers, the white icon label may no longer appear, and magnification may not work either. To fix this problem, restart the computer. This appears to have been fixed for newer Macs.
• After inverting the colors for a long period of time, you may change back and find that the colors in some applications are very messed up. To fix that, just restart the computer.
• This may also damage the system, so please use this neat little trick in moderation, or else your computer may not work properly.