How do you brighten a computer screen?
There are two ways to adjust your display brightness.
1. Use the Function Keys.
Tap the F1 key to dim your display, tap the F2 key to make it brighter.
NOTE: If the display does not respond, hold down the fn key in the lower left corner of the keyboard while tapping the F1 or F2 key. Some older keyboards may have the brightness icons on the F14 and F15 keys. Use the key with the correct icon to brighten or dim the display.
2. Use System Preferences.
Click on the gray apple in the upper left of your Finder menu bar. Select System Preferences from the drop down menu. Select the Displays preference in the Hardware row. Use the Brightness slider to adjust the brightness.