What about just using the "brightness/contrast" option, or does adjusting the curves give a better result?
The "brightness/contrast" command should not be used on any image you actually care about. Photoshop’s "brightness/contrast" and "color balance" commands are only there for novices who don’t want to take the time to learn Levels or Curves and don’t care about quality; they are "linear" commands, which means they degrade the quality of the image by removing detail from the hilights and/or shadows of the image.
Curves can do absolutely, positively everything that Brightness/Contrast and Color Balance can do, but Curves is a "nonlinear" command; it does not degrade image quality by clipping image detail.
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