If things are looking over-exposed or have too much contrast:
1. Go to System Preferences > Universal Access > Seeing
2. Under Display: section you will see an Enhance contrast slider
3. Slide it all the way to the left to Normal
4. Alternately you can use the key command: Hold Control-Option-Command keys down and tap the comma key to reduce contrast.
Unfortunately, a screen capture will not show the issue.
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