How To Disable Adaptive Brightness and Contrast in WindowsIf your Surface Pro, Laptop or Book display suddenly shifts brightness at night time or when switching applications these simple registry tricks will solve it.
Adaptive brightness and adaptive contrast are two mechanisms by which Windows, the Surface Book, Laptops, and Surface Pro change the brightness and contrast of the screen depending on the ambient conditions and what you are viewing.
Adaptive brightness in Windows 10 works similarly to how your phone adjusts the screen's brightness depending on the light it perceives. This prevents the screen from being brightly lit at all times and saves battery life when the computer isn't being charged.
Adaptive contrast auto-adjusts aspects of the screen based on light or dark scenes. This can give a richer experience to gaming and movies. However, it isn't easy to work with photos where you need accurate colour representation. It can also be annoying if you regularly switch between a "dark mode" application and a white or light web page as the screen ramps up the brightness.
How to Fix Surface Screen Dimming Problems
Disable Adaptive Brightness in Windows 10
You can easily turn the adaptive brightness feature on or off from the advanced options in your current power plan. To do that, head to the Start Menu and search for "Power & Sleep settings". Open the link that appears.
In the related settings section, click the link for Additional Power Settings.
In the window that pops up, click on Change Plan Settings next to the selected power plan.
In this new window, find and click on the link for "Change advanced power settings".
Now locate the Display options, then Enable adaptive brightness. You can turn the options off to disable Adaptive Brightness in Windows 10 from here.
Disable Adaptive Contrast in Windows 10
Unfortunately, there is no easy way to turn off the adaptive contrast. While many users combine the two, disabling auto-brightness won't solve this behaviour if it bothers you. Microsoft does not offer any way to turn off adaptive contrast through the Windows 10 interface, so the registry is the only way to do it.
Warning: Modifying the system registry can have dire repercussions if not followed precisely, including driver failures, system instability, or inability to boot into Windows. Users are always encouraged to run a system backup restore point before making any changes to the registry.
Launch RegEdit and navigate to Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001.
Scroll down to mid-page, and then find FeatureTestControl and double-click to edit the DWORD Value. Change Value data from 9240 (default) to 9250 (leave in base hexadecimal).
If the value does not exist in this location, instead navigate to Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000. There is a difference between Surface Books, Surface Pro and Windows update versions.
Hit OK to save the changes and restart the Surface to apply changes.
To re-enable the feature, retrace the above steps, change 9250 back to 9240, save, and restart.
