Windows 10 laptop changes brightness depending on the screen contents
Solution 1:
1.Go to Control Panel > Hardware and Sound > Power Options, then click on "Change plan settings" next to your active power plan.
2.Click on "Change advanced power settings."
3.Scroll down to Display, then under Enable adaptive brightness, switch it off for both the battery and plugged in modes.
Solution 2:
For me I had to disable it by right-clicking on the desktop and choosing "Intel(R) Graphics Control Panel" (it's only accessible from the desktop, not the Start Menu). "Power", "Display Power Saving Technology", "Disable". Hope that helps someone.