You can do almost everything that most images need in terms of global corrections to tone and color using Levels, Curves, and Hue/Saturation. But sometimes none of these tools offers the quickest or best solution. We've emphasized them in this chapter because mastery of them really is part of the core of Photoshop skills. But if you ignore the other tools, you may create extra work for yourself. Knowledge of the tools helps you identify image problems, but equally important, that knowledge helps you come up with a plan to fix those problems.
In this chapter, we've concentrated on the basic functionality of the image adjustment tools to make global edits to entire images. In the next chapter, we'll show you how to use these tools, and some others, in more nuanced ways to make both global and local corrections.