My father in law uses a mac. He once asked me to fix something there for him. So I turned it on and I thought my eyes where bleeding. He had the contrast on the highest level. It was so bad you couldn't even recognize the buttons on the screen. So I changed the contrast to a degree that I could recognize something except for white on the screen. After fixing his problem I asked him why his contrast was set so high. He said that the colors on the screen were only right when the contrast is set high and that I should change it back.