In a B&W scan from a textbook, I've already lightened it overall using Image/Adjustments/Shadows and Highlights - but the darks are still very dark, yet there are some very white areas that are very white. I don't use photoshop to work with pre-printed images usually so not sure how to resolve this. I'm in CS5.
Years ago in a workshop I learned to work with levels using eyedroppers to balance out heavy blacks and really white whites, but can't find the notes now. All help appreciated -