Can the same brightness shortcuts use different step sizes on different displays?

Yes, with a script that selects the display and chooses an adjustment amount before sending the brightness command. BetterDisplay’s ordinary standard and fine keyboard-step settings apply to all displays. They do not automatically switch between a laptop and desk preset.

A useful script workflow is:

  1. Identify the display you want to adjust. Use displayWithFocus for the display containing the focused window, or displayWithMouse for the display under the pointer.
  2. Compare that display’s identifier with the displays in your configuration and choose the desired step—for example, one percentage point for the built-in display and a larger step for the external monitor.
  3. Apply a positive or negative brightness offset to that explicit display. Use the same chosen target for the lookup and write so a pointer or focus change does not redirect the adjustment midway.
  4. Assign the script to the keyboard combination through a Shortcuts Run Shell Script action, or through a keyboard/mouse utility that can run commands.

The CLI’s identifiers query supplies display identities. A brightness value such as 1% with offset means one percentage point of the control’s range, not one percent of its current brightness. See CLI examples for targeting and offset syntax, and Shortcuts for integration.

Smaller steps on all displays

For two-percentage-point requests, open Settings > Keyboard > Configure Steps for Range-Based Controls…, set Number of logical steps in the entire range to 100 and Standard step size to 2. A Fine step size of 1 requests one percentage point. These settings also affect other range-based keyboard adjustments, including volume. They apply across displays.

The displayed change can still differ when a controller maps or rounds the request, or combines hardware brightness with software dimming or upscaling. A monitor can only reproduce its supported hardware levels. For native brightness and volume keys, Shift+Option requests the fine step unless Make fine scale default reverses the relationship.

If the useful hardware range occupies only a small part of the slider, inspect brightness under Settings > Displays > [display] > Device Control > DDC Control > Configure Controls…. A lower DDC value range maximum limits the highest hardware level requested. DDC value mapping skew changes how the app’s scale maps onto hardware values. Neither creates additional physical brightness levels.

If you only want hardware brightness and do not need dimming below its minimum, turn off Combined brightness in the display’s Device Control > Image Adjustments section while retaining a working hardware controller. This is simpler than moving the software-dimming switchover point solely to avoid the software range. Adjust one setting at a time and compare the actual monitor response. The best maximum is specific to the display.

If fixed amounts on separately assigned keys are enough, per-display Shortcuts using Image Adjustment Offset are simpler. If you want smaller steps everywhere, use Configure Steps for Range-Based Controls instead.