Hey there, As the tittle says, i have a pretty ugly problem with QuickTime Player and Safari. It is as follow: I open a video of any type in either QuickTime or Safari (YouTube, Vimeo). As soon as i go Full-Screen, it immediately changes the Contrast (or Gamma). Blacks start to get crushed, and highlights get overexposed. As soon as i move the mouse though, it goes back to normal. Once i let the mouse rest, and it disappears, the contrast shift is almost immediately back again. The following is an example (Screenshots) of a personal video, that shows this very problem pretty well. First image, this how it was displayed on my Cameras monitor, and is pretty much correct, i took this a split second before it turned "ugly" (Don't mind the menu bar showing, in both images the mouse was hidden, i had to do record a screen recording to take these, since the normal screenshots didn't capture the effect): Now the issue that i have, just a split second after the interface disappeared, it shows like this: This has been an issue for a long time now. And after some research, i just haven't seen any posts specifically about this issue. Maybe i just clicked some option somewhere that causes this, or maybe i just used the wrong search terms. Maybe it is that im studying movie making, and therefore notice the extremely ugly exposure issues this creates, in places where it should not be. It bothers me quite a bit. And makes it more annoying that it should be to check recordings, because it changes the way my video looks. I constantly have to wave the mouse around like an idiot, to keep it away, only to be treated by the new "feature" that enlarges my mouse when waving around, thinking that it, being missing is the issue (a thing in El Capitan, not quite useful for me Anyway, this has been quite a headache, and also happens with Fullscreen online streaming content with Safari. But only in Safari. In Chrome, it is not there, same for players like VLC. But since Chrome is consuming a huge amount of power, and just isn't cutout to work as well with Mac as Safari is, im not quite fond of using it. Hope there is a solution, or a simple reason for why. Best Wishes, and Merry Christmas/New Year to you!) Julian Blau.