The adjustments you’ve seen so far are OK when you’re just starting out with Photoshop, and they’re darn handy when you’re pressed for time. But to become a serious pixel wrangler, you’ve got to kick it up a notch and learn to use Levels and Curves.
With a single Levels adjustment, you can fix lighting problems, increase contrast, and—in some cases—balance the color in your image. (If you’ve got major color problems, you need to use Curves; skip ahead to Working with Curves to learn how.) Levels adjustments change the intensity levels of shadows, midtones, and highlights (hence the tool’s name). They’re a very visual and intuitive way to improve images. And because they’re available as Adjustment layers (yay!), they’re nondestructive and won’t harm your original image; plus they come with an automatic layer mask.
In this section, you’ll learn how to use Levels adjustments in a few different ways so you can pick the one you like best. But first, you need to get up close and personal with the mighty histogram, your secret decoder ring for interpreting the info in your photos.
A histogram (Figure 10-13) is a visual representation—a collection of tiny bar graphs, to be precise—of the info contained in an image. Once you learn how to read it, you’ll gain an immensely valuable understanding of why images look the way they do. More importantly, you’ll learn how to tweak the histogram itself or (more commonly) make changes with other tools while ...