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Brightness control settings and actions

The configuration of the brightness control policies (settings) is performed through updates to the Windows power policy. For example, the Windows power policy includes the default display brightness level when the system is plugged in and when it is running on battery. This section provides a detailed list of power policy settings related to display and brightness.

In this section


Display brightness

The default display brightness is configured as a power policy setting with separate on-battery and plugged-in brightness levels.

ALS-based automatic brightness (adaptive brightness)

On PCs that have an integrated ambient light sensor (ALS), if the adaptive brightness feature is enabled, Windows automatically calculates the optimal brightness level based on the brightness slider setting and the current ambient lighting. The enable adaptive brightness setting can be used to enable or disable this feature.

Automatic display dimming

Windows automatically reduces the brightness level of an integrated display after a period of user inactivity. The functionality of this feature is configured with a set of power policy settings.

Other settings

The rest of the power policy settings related to display and brightness are enumerated below. These settings are enumerated for reference and should not be changed from their default values by system manufacturers.

Guidelines for brightness control policy configuration

Windows 8 ships with carefully selected default power policy settings.

Best practices for software developers

In Windows Vista and earlier versions of Windows, APIs are provided to enable applications to control the display brightness level. System manufacturers typically use these APIs to enable value-added extensions for controlling the display brightness level on systems where the keyboard hot keys are not implemented using Advanced Configuration and Power Interface (ACPI) notifications or Human Interface Device (HID).


System manufacturers should understand the brightness control policies for Windows 8 and customize a subset of them as appropriate for their systems. For more details, see Guidelines for brightness control policy configuration and Table 1 Settings and customization requirements in Guidelines for brightness control policy configuration.



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