Open the file you wish to work with in Photoshop.
Duplicate the Background layer by dragging it onto the Create A New Layer button in the Layers palette.
Click on the Eye icon to make the Background layer invisible (since we won't be using it).
Select Image ▸ Adjustments ▸ Levels with the Background Copy layer active.
Move the white point slider to 235. As you make this adjustment, notice that the gray point slider also moves to open the midtones of the image.
Change the name of this ...