Why does my phones screen become dimmer automatically?

[AC Question]

When calling some one my screen became dimmer automatically although the brightness was 100%. Also when it does that i cant see to end the call or change the volume. This is happening on samsung galaxy s7 edge.

 

[YouBlue_dev]

Pull down the tray all the way so you can see the brightness control. Tap the drop down arrow on the right, and turn off "Auto brightness"

 

[Golfdriver97]

Welcome to the forums. Do you have auto brightness enabled? I think you can check in either settings>display, or by pulling the notification shade down.