The missing brightness slider for your external display
macOS has no brightness control for most external displays. Lumac adds one to the menu bar and the brightness keys, and puts a MacBook to sleep when you close its lid.
Free and open source · macOS 14 or later · Apple silicon
Brightness keys work on the external display
When the pointer is on the external display, F1 and F2 change its brightness in 16 steps, as on the MacBook. On the MacBook’s screen, the keys work as usual.
The external display follows the MacBook’s brightness
With Follow turned on, the external display changes brightness whenever the MacBook does, including the automatic changes macOS makes from the light sensor.
The MacBook sleeps when you close its lid
With a display plugged in, closing the lid doesn’t put a MacBook to sleep: macOS moves everything to the display and keeps working (clamshell mode). With Lumac, the Mac and the display go to sleep.
Without Lumac
When you close the lid, the Mac stays awake and the display stays on.
With Lumac
When you close the lid, the Mac goes to sleep and the display turns off.
Which connections and Macs work
Brightness control needs a connection that passes commands to the display. Sleep on lid close works with any display.
USB-C to DisplayPort
All settings in the panel work
USB-C display
All settings in the panel work
HDMI port of an M1 MacBook Pro
All settings in the panel work
USB-C hub with HDMI
Lumac darkens the picture instead of the backlight
DisplayLink adapter
Not supported
Intel Mac
Apple silicon only
Tested on a MacBook Pro with M1 Pro and an LG HDR 4K. Another setup? Tell me on GitHub whether it works.
Frequently asked questions
Is it free?
Yes. Lumac is open source under the MIT license, with no account and no in-app purchase.
Why isn’t it on the Mac App Store?
App Store apps can’t talk to a display over its cable or put the Mac to sleep. Each release is signed and notarized by Apple instead.
Does Lumac collect any data?
No. Lumac never connects to the internet. Its settings stay on your Mac.
Why does it ask for Accessibility access?
For the brightness keys only. The option stays off until you turn it on in the panel.
Download Lumac
macOS 14 or later · Apple silicon · Signed and notarized
brew install --cask eliorpom-cmd/tap/lumac