Look again on the setup to get it out of that mode.
I have a Samsung UN32ES6500 and am using it as a computer monitor via an hdmi cable to my computer. For some reason, whenever I turn it on, it'll look fine but after anywhere for 2-10 minutes, the picture will reset to this heavy-contrast or heavy-brightness picture where darks are not as prevalent.
I have gone through the settings over and over and cannot find anything that causes this, it is currently set to the picture mode Entertain, the only other option is standard but when I set the monitor's "name" to PC, it automatically set itself to Entertain so I'm not sure changing that will solve the problem or only worsen the picture for PC use.
What is going on here and how can I fix it? All help will be greatly appreciated!