Why does my screen capture turn dark?

[Android Central Question]

Whenever I take a screen grab, either using the phone's buttons or a 3rd party app (DU Recorder) the image is very dim. It also happens when screen grabbing video. I've tried adjusting all my brightness settings and preferences and it doesn't change.
I'm using a Galaxy Note 8.

 

[JoshCS2000]

This is a screen grab with full brightness.

 

[ManiacJoe]

Any chance you have a blue-light filter or other screen/brightness control app running?