Lumendial — Brightness Control for Every Display

Lumendial puts a brightness slider for every connected display in the Mac menu bar: the Mac's own screen and external monitors, side by side. It adds presets, keyboard shortcuts and an evening schedule, and it needs no permissions.

A slider for each screen

Every display gets its own slider, named the way macOS names it, with its level shown beside it. All displays at the top moves them together.

The monitor's own backlight

The Mac's built-in screen, and Apple displays, are set through the same system brightness service as the brightness keys. External monitors are checked when they connect, and if a monitor answers over DDC/CI, its slider drives the real backlight and a smaller contrast slider appears.

When a monitor does not answer

DDC support depends on the monitor, the cable and any dock or adapter in between. A monitor that stays silent is dimmed in software instead, by scaling its colour output. Screenshots and screen recordings stay bright, and normal colours come back when Lumendial quits, or at the next launch after a crash.

Day, Evening, Night

One click sets every display to a preset. Any level can be saved as a preset of its own, up to six, and the right-click menu offers them all without opening the panel.

Brighter and dimmer, from anywhere

Control-Option and an arrow key move every display one step of sixteen, from any app, and the menu bar shows the new level.

Dims itself in the evening

Pick a time and a preset. Every display dims then, and Day comes back at the morning time. It works from the clock alone, so no location is needed.

How it works

• Click the menu bar icon and the panel lists every connected display by the name macOS gives it, each with its own slider and percentage.
• Drag All displays at the top to move every screen together, or drag one display's slider to change just that screen.
• Press a preset: Day, Evening and Night set every display to 100%, 60% and 25%. Save current stores the present level under a name, up to six.
• Press Control-Option-Up or Down Arrow from any app to move every display one step of sixteen. The menu bar shows the new level for a moment.
• Turn on Dim in the evening, pick a time and a preset, and a time to go back to Day in the morning. It uses the clock only, never location.

Opening it the first time

Lumendial is signed and notarized by Apple, so it opens with a normal double-click. Lumendial asks for no permissions at all: no Accessibility, no Screen Recording, no location.

Will it control my external monitor directly?

Only if the monitor answers DDC/CI commands, and not every setup does. Some monitors need DDC/CI switched on in their own on-screen menu, most TVs never answer, and HDMI on some Macs and some docks and adapters does not pass the commands through. A direct HDMI or DisplayPort cable is the best chance. Where DDC is not available, software dimming still works, and the panel shows which method each display uses.

Does software dimming affect screenshots or colours?

Screenshots and screen recordings are not darkened. Dimming works on top of the current colours, including Night Shift and colour profiles, and they return exactly when the slider goes back to 100%.

What if the app quits unexpectedly?

Quitting normally restores any software-dimmed display first. After a crash, opening Lumendial again restores normal colours at launch, and logging out and back in does the same.

Does it need permissions or an account?

No. It asks for no Accessibility, Screen Recording or location access, has no account, and everything stays on the Mac.

Which Macs does it run on?

Any Mac with Apple silicon or Intel running macOS 13 Ventura or later.