PanelCtl

PanelCtl started as an experiment to see what macOS safely detail and control with external monitors.

The end result is a pure-black window on selected displays. An idle timeout intervenes to protect OLED monitors with a black screen when I step aware from my workspace or I’m on a call and don’t need my screens. That is useful when a long video call leaves static pixels on a side monitor, or when I step away from the desk in the middle of a long day.

# Black out one display after five idle minutes, then keep watching.
panelctl blackout --display DISPLAY_UUID --idle-after 5m --watch

# Black out every display after idle, then sleep them after 30 minutes.
panelctl blackout --all --idle-after 5m --sleep-after 30m --keep-displays-awake

It grew into a macOS CLI and menu-bar app for display inventory, OLED blackouts, display sleep, configurable idle and restore timers, and experimental DDC brightness control.

A blackout minimizes OLED pixel emission. However, it does not power down display electronics or guarantee a panel compensation cycle. For a long unattended stretch, all-display sleep is still the better option.