How can I dim a monitor below its lowest hardware brightness?

Enable software dimming alongside hardware brightness, then use Combined brightness to adjust both with one slider. A monitor’s lowest hardware setting can still be visibly bright. Software dimming darkens the image further without requiring the monitor to lower its backlight beyond that limit.

  1. Open Settings > Displays > [display] > Device Control and keep a working hardware-brightness controller enabled. For a compatible external monitor, this is commonly Brightness (hardware) under DDC Control.
  2. Enable Enable software-based video adjustments in the display’s Image Adjustments section.
  3. Enable Combined brightness and test the main brightness slider. With both paths working, the lower part of its range adds software dimming after the configured hardware minimum is reached.

You do not need to hold the monitor at 100% and rely only on software dimming. Combined brightness manages both parts of the range. If another app is also changing brightness, quit that app while checking the setup so its adjustments do not compete with BetterDisplay.

If software dimming works but hardware brightness does not, check the DDC connection and enabled controller separately. Combined brightness needs both hardware and software brightness controllers to be available. Enabling the preference cannot create missing monitor support. Software dimming can also work on its own, but then the monitor’s own brightness number will remain unchanged.

See why brightness percentages differ for the combined scale and Device Control for the software-dimming switchover point. Software dimming changes the image. It is not a measurement of backlight output or power consumption.

To keep hardware brightness above a chosen floor while still dimming the image, open the display’s Image Adjustments > Image Adjustment Settings… and set Combined brightness - minimum allowed hardware brightness level. This Pro setting uses the hardware controller’s own percentage scale. The lower combined range then uses software dimming at that floor. It does not measure flicker or establish a universally flicker-free brightness level for the panel.