The brightness changes with the colors displayed à l’écran on my Lenovo Thinkpads with Intel HD Graphics. Light colors make the screen brighter, dark make it darker. Same behavior in Windows 8.1 and 10.
The “adaptive brightness” feature in Windows is disabled.
Just found a suggestion that solved my problem here.
It is the Intel “Display Power Saving Technology” that is to blame.
Disable it like so:
Launch “Intel HD Graphics Panneau de configuration” by right clicking and selecting “Graphics Properties…” from your Intel HD Graphics tray icon
Click Power
Choose “On battery”
Select “Disable” for Display Power Saving Technology
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