What can I try if brightness upscaling stops increasing brightness?

Check which brightness-control method is active. If software upscaling stops changing the image even though the slider still moves above 100%, temporarily disabling color-table control can help isolate a compatibility problem with that method.

If the upscaling option is missing entirely, first check whether the display supports it. Software upscaling requires an eligible HDR/XDR mode or sufficient extended brightness headroom, as well as Pro to use it. A Retina display is not automatically an XDR display, and ordinary SDR hardware without that headroom cannot gain it just by enabling an app setting.

If upscaling is enabled but the main brightness slider only changes hardware brightness, check Combined brightness under the display’s Device Control settings. Combined control brings supported hardware brightness, software dimming and upscaling into one slider. With it disabled, use the separate software-brightness adjustment under Image Adjustments, where available. Its upscaling headroom depends on the current hardware brightness. Enabling upscaling does not make a hardware-only slider control that extra range.

Open Settings > Displays > Overview > Software XDR/HDR Upscaling and Dimming and turn off Allow color table control (turn this off for compatibility mode). Retest the same adjustment. BetterDisplay reconfigures its controllers and may use another available method, such as compositor filtering. The fallback depends on the display and enabled controls. It is not guaranteed to reproduce every adjustment.

If this restores upscaling, compare the selected color profile and other apps that alter display colors. The result narrows the problem to the affected adjustment path. It does not by itself identify a defective profile, a conflicting app or a hardware fault. See custom-profile compatibility.

For a compatible built-in XDR display, direct upscaling is another available method. It requires Pro and replaces the default macOS brightness-control path.

  1. Open Settings > Displays > [built-in display] > Device Control and enable Allow direct control and XDR upscaling.
  2. If software upscaling is active, turn off ordinary Brightness Upscaling in the display’s app menu.
  3. Activate Brightness Upscaling (Direct) in the app menu.
  4. Configure BetterDisplay to handle the brightness keys so they can adjust the direct brightness range.

This method is for compatible built-in XDR displays, not external Studio Display XDR units. See direct brightness settings for its range and options.

If it makes no difference, restore the setting and check the display’s supported controls and active upscaling method. For brief dips during direct XDR upscaling, see the EDR setting instead. The brightness and dimming reference explains the global options.