Photoshop Adjusting Levels.

When adjusting levels in Photoshop use Adjustment Layers so you are doing “No Destructive Editing”

Go to your adjustment layers pallet.
Choose levels.
Hold down the “OPTION” key while sliding the sliders and adjusting your histogram.
Notice when the color starts being revealed. That is a good stopping point.

Start Image:

Notice adjustment Holding Option Down

 See Corrected Image: