

Tweak Brightness Manually On Third-Party External Display Adjust Brightness for An External Display and Dim Method 1. For keys set up to work as standard F-keys rather than special action buttons, press and latch on the Fn key while you tap them.Simply hold down the keys to reduce or increase brightness intensity.

The F14 and F15 buttons keys with sun-like icons on them also execute this command.

But it’s a double-edged sword as this intermittent brightness makes you fly into a rage if it’s disrupting. Mac has a built-in auto-brightness feature that fine-tunes the luminosity of the display and keyboard in tandem with ambient light.
