AutoDim

AutoDim is a macOS menu bar app that dims your screen and removes blue light on a daily schedule, so your display winds down before bedtime.

Credit

AutoDim is a fork of DisplayFilter by Yaşar Koçal (MIT licensed). The menu bar app, gamma-table dimming and color filters are his work; the daily schedule, color-temperature phases, persistence, launch at login and multi-display fixes were added on top. The original copyright notice is kept in LICENSE. DisplayFilter was inspired by MonitorControl and f.lux.

Features

• Built-in daily schedule: full brightness and no filter from 07:00, then three progressively dimmer and warmer evening phases (defaults 20:00, 22:00, 23:00), each fading in over 10 minutes; all times, brightness and color temperatures are editable
• Pause: "Until next phase", "For 1 hour" or "Until tomorrow" returns the screen to normal, then the schedule resumes
• Manual changes hold until the next scheduled boundary, then the schedule resumes
• Software brightness control below the display's native level, and warm manual color filters (orange, red) with adjustable intensity
• Applies to all connected displays
• Lives in the menu bar, with a Now tab and a Schedule tab

Brightness is a software gamma adjustment. It does not change the display's hardware backlight.

Install

Requires macOS 15.0 or later on Apple Silicon (the build targets arm64; Intel Macs are not supported).

Download: get the current AutoDim ZIP from Releases, unzip it and move AutoDim.app to /Applications. The app is ad-hoc signed and not notarized, so macOS blocks the first launch. Open System Settings > Privacy & Security, choose Open Anyway for AutoDim, then confirm Open. Do not disable Gatekeeper or remove the app's quarantine attribute.

Or build from source:

1. Clone this repository.
2. Run ./build.sh (needs only the Xcode Command Line Tools, not full Xcode). It builds and ad-hoc signs build/AutoDim.app.
3. Copy build/AutoDim.app to /Applications and open it.
4. To start it at login, add it in System Settings, General, Login Items. The schedule only runs while the app is open.

Other gamma-based tools such as f.lux change the same display settings; run only one at a time.

Why these defaults

What the research supports, and what it does not:

• Evidence: expert consensus recommends low evening light starting at least 3 hours before bedtime (Brown et al. 2022), and evening light suppresses melatonin in a dose-dependent way (Gooley et al. 2011, Phillips et al. 2019).
• Evidence: on a tablet, a warm filter alone did not reduce melatonin suppression, but a lower brightness combined with the filter did (Nagare et al. 2019). Brightness does most of the work here; warmth is secondary.
• Evidence: in a display study, melanopic content (the part of the light the body clock responds to) drove melatonin, sleep latency and alertness effects, independent of how the screen looked (PMC9974389). Removing blue lowers it.
• Not shown: I found no randomized trial showing that software filters like this improve sleep, and people differ more than 50-fold in sensitivity to evening light. The phase times and strengths are defaults to tune, not tested doses, and room lighting matters too.

Development

• ./build.sh debug adds the --simulate-time HH:MM and --debug-window launch arguments for testing the schedule.
• ./build.sh check runs the schedule math checks.
• VERSION=1.0.1 ./build.sh package creates build/AutoDim-1.0.1.zip and its SHA-256 file, then verifies the extracted app signature. Use this command for release uploads rather than Finder's Compress action.
• The Xcode project (DisplayFilter.xcodeproj) also builds the app but has not been built on the maintainer's machine.

License

MIT, see LICENSE.