Luma is a tiny macOS menu bar app that puts every monitor on your keyboard: Apple Studio Display, DDC externals, the built-in panel. Keys, knobs, scroll, sliders. Free and open source.
This is a public beta. It works on the hardware it's been tested on, but DDC monitors vary wildly. If yours misbehaves, open an issue and Luma will tell you what it saw (⚙ → Copy Diagnostics).
0.2.0 beta 2 · free · open source (MIT) · Apple Silicon only · macOS 13+ · under 1 MB · native Swift
That's the whole app. You can honestly stop here: the download button is right up there, and it does exactly what it says. Still reading? Wondering why the simplest key on your keyboard needed rescuing, or why a brightness slider got this much landing page? Fair. Scroll on.
↓Your brightness keys reach the built-in panel, and Apple's own displays if you know the hidden Ctrl shortcut. Plug in anything else and macOS offers nothing: no keys, no slider, no Control Center. Just the buttons on the back of the monitor.
A small sample of people running into the same wall, 2011 to now. Every card links to the original post.
"Is is possible to have the brightness keys (F1 & F2) change both the main display (laptop screen) and the secondary display…?"
W wu_tang_chrisHacker News HACKER NEWS"This is the biggest inconvenience and overall PITA docking my MBP, it annoys me constantly on a daily basis."
G Gloria Mdiscussions.apple.com APPLE SUPPORT"…WOW it is too bright. I went to adjust it and it is not possible. My keyboard brightness controls don't work either."
S ScoobyMcDooforums.macrumors.com MACRUMORS"The brightness buttons (F1 & F2) on my MBP only control the brightness of the internal monitor - not the external."
A aaomidiHacker News HACKER NEWS"I'm so annoyed my OS doesn't integrate with DDC :/"
L u/Lobster513r/MacOS REDDIT"So I've tested a few 4k monitors via USB-C to see if I can control the monitor brightness with the media keys. You can't."
G guitarguy19forums.macrumors.com MACRUMORS"Hooked up today…and now the ASD brightness will not adjust from the keyboard buttons."
T u/Technoistr/MacOS REDDIT"It's just frustrating that it's not built into macOS. It should be."
B bmitcHacker News HACKER NEWS"It's not that the keys don't work. It's that you just simply cannot do it even from the OS."
Brightness reaches macOS by two different event routes depending on your keyboard. Luma intercepts both: standard brightness keys, Apple media keys, QMK/VIA rotary encoders. And you can scroll the menu bar icon for good measure.
Pick your default, then hold ⌥ (configurable: ⌃ ⇧ ⌘) to temporarily use the other routing for a single press. When individual levels differ, the master slider says Mixed instead of pretending their average is a useful setting.
A notch-style pill slides in from the top of whichever display you're on, or vertically from the left or right edge. Never on the wrong screen, never in your way.
macOS already warms your screen after dark. Luma puts it where the brightness lives: one master switch, a warmth slider, sunset or custom scheduling, and a temporary Warm now override. It drives Night Shift itself rather than tinting over the top, so it survives sleep and wake and stacks cleanly with sub-zero dimming.
Right-click for presets, per-display levels, pause, and exclusions. Left-click for sliders. Scroll to adjust without clicking at all. Nothing to open, nothing to find.
Studio Display and built-ins use Apple's native brightness path; everything else uses DDC/CI. Gamma stays untouched unless you deliberately enable sub-zero dimming.
DDC monitors reset when power-cycled. Luma restores each display's last level the moment it reconnects.
The warmth slider drives macOS Night Shift directly, so it composes with sub-zero dimming instead of fighting it, and survives sleep and wake. Sunset and sunrise are computed on-device; nothing is sent anywhere.
No dock icon, a menu bar mark that doubles as a brightness gauge, a pause switch for when you need it gone. A under 1 MB native app, ~50 MB RAM, one process, 0% idle CPU , no webview, no display polling, everything event-driven.
Only to intercept brightness keys before macOS routes them to the built-in display. It's requested once, and the sliders work fine without it. Luma never reads what you type: it consumes exactly two keys.
Only if you pick the Sunset schedule, and only to print tonight's real sunset and sunrise beside it. Night Shift's own daemon knows those times but won't hand them over, so Luma works them out from a one-time, low-accuracy location fix. Decline and everything still works , the label just reads "sunset and sunrise" instead of the times. Nothing is transmitted or saved.
Luma ships unsigned (no $99 developer program between you and a brightness slider). Right-click → Open → Open the first time, or run xattr -dr com.apple.quarantine /Applications/Luma.app. The install guide walks through it with screenshots.
Apple displays (Studio Display, Pro Display XDR, UltraFine, built-ins) work natively. Almost any other monitor works over DDC/CI; enable it in your monitor's OSD menu if it isn't already. Known gaps: DisplayLink docks don't pass DDC through, and M1-era HDMI ports are quirky.
Not yet , Luma is Apple Silicon only (M1 and later). The way macOS exposes a monitor's DDC channel is completely different on Intel, and that path isn't written yet. It's on the list, but it will ship when someone with an Intel Mac can test it rather than before.
That's the dock, not Luma. Many docks and hubs, especially ones that drive several screens over a single cable, don't relay DDC/CI to the monitors behind them. macOS has no way to report this, so nothing can detect it or work around it, and the monitor simply never answers. Plugging the display directly into the Mac is the fix. If you'd rather keep the dock, turn on Dim below minimum and Luma will dim that screen in software instead.
Controlling display hardware requires private macOS frameworks, the same ones every serious brightness tool uses. Apple doesn't allow those in the App Store, which is why none of the apps in this category live there.
Yes. MIT-licensed, no Pro tier, no daily adjustment caps, no unlock codes. It exists because the paid alternatives kept locking basic things away.
macOS has no brightness control for third-party monitors, so I built a small app for it. On a third-party keyboard the brightness keys only ever reach the built in panel, whatever else is plugged in.
It works through a private framework, which is a workaround rather than a design. I reverse engineered it against a single portable USB-C monitor, on one Mac.
The code beside this is not a patch. It is just evidence that the hard part is small, and a record of what I had to guess at.
The ask is only this: please consider making it native. If it ever ships, I will retire this app gladly.
P.S. MIT licensed. Take anything useful.
0.2.0 beta 2 · free · MIT · Apple Silicon · macOS 13+ · install guide · or build from source
Drag Luma to Applications. macOS may block the first open; Accessibility is only needed for brightness keys.
Both commands in one line. The trust step is not optional: Homebrew will not load a cask from a third-party tap without it.
brew trust heymykro/tap && brew install --cask heymykro/tap/luma