Adjust screen brightness directly from taskbar in Windows 8?

Solution 1:

• iBrightness might be what you're looking for:

  

• Of course there are various other apps (although perhaps not providing direct access via a popup) that are progressively ugly in terms of UI, such as Display Tuner, ScreenBright, Desktop Lighter...

  

• You can also create shortcuts with keyboard shortcuts to NirCmd, and in the Target field specify parameters such as changebrightness <level> (where level can be +ve or -ve). The following commands will even automate the creation of the shortcuts for you (edit as required):

  nircmd.exe cmdshortcutkey "~$folder.desktop$" "Decrease Brightness" "Ctrl+Alt+F9" changebrightness -10
  nircmd.exe cmdshortcutkey "~$folder.desktop$" "Increase Brightness" "Ctrl+Alt+F10" changebrightness 10
  

Solution 2:

As of June of 2013, if you have a Surface with a Touch cover you can also use Fn + Del and Fn + Backspace to adjust brightness.

Other shortcuts include:

• Fn + Caps: Locks F1-F12 into being function keys.
• Fn + Spacebar: Print Screen
• Fn + Spacebar + Alt: Print Screen for the in-focus app only
• Fn + Del: Brightness Up
• Fn + Backspace: Brightness Down
• Fn + left: Home
• Fn + right: End
• Fn + up: Page Up
• Fn + down: Page Down

http://www.wpcentral.com/new-hot-keys-and-functionality-coming-surface-keyboards-next-week