Instructions

1

Choose "Preferences" from the applications menu on the Macintosh operating system, Mac OS. Whenever you want to change the look and feel of the Mac OS such as making adjustments to sound and brightness go to "Preferences."
2

Select "System Preferences" then choose "Displays." This step opens the display preference settings. Click on the "Display" tab.
3

Adjust the brightness by moving the Brightness slider with your mouse. Moving it left makes the screen dimmer. Moving the slider right makes the screen brighter.
4

Read the system User's Guide or Reference manuals if you have any questions.