Scene clip in Video Editor affects the image strip above it In the Video Sequence Editor, I have added a scene and over top I added an image strip.  



The image strip is set to 100% opacity and therefore should not be affected by whether the scene is underneath it or not.

However, frame 15 is darker than frame 30.



What could be the cause of this?
I submitted a false bug report on this issue and a developer, Sergey, explained the problem: Color Management had been turned off.

Color management is on by default, and Sergey suggests not messing with it.  (someone else edited my .blend file)

To re-enable Color Management, go to the Scene tab of the Properties window and under Display Device, select sRGB.



The problem should be gone.  Please see the bug report for details on why this occurs.