how would you change the lighting/contrast of a game?

Okay, so in these pictures, the game seems to have a completely different lighting/contrast with the default settings, making my skin/block color appear different. http://prntscr.com/grmfk5 http://prntscr.com/grmha6

how would you be able to edit the lighting/contrast so that it would look like this on my game?

https://www.youtube.com/watch?v=Xoj5KI4Sbr4