The BitsPerPixel property indicates the actual number of bits per pixel representing the display. This may be scaled to the ...

The BitsPerPixel property indicates the actual number of bits per pixel representing the display.  This may be scaled to the current video setting (represented by the ActualColorResolution property) of the user.
Example: 8  
This property has been deprecated in favor of a corresponding property(s) contained in the Win32_VideoController, Win32_DesktopMonitor and//or CIM_VideoControllerResolution