This chapter concentrates on a really useful layer type in Photoshop, the adjustment layer. This layer type was first introduced in version 4.0, and it offers a really flexible way to make color and tonal adjustments to your images.
You've probably used quite a few of the adjustment commands under the Image → Adjustments menu. These commands let you tweak various aspects of your image, such as brightness and contrast, hue and saturation levels, and color balance. Wonderful though these commands are, they're all destructive, which means they permanently alter the pixels of your image. Each time you go back and make another adjustment, you lose more and more image detail, and you can't reverse the effect of an adjustment, either.
You can, of course, use the History palette to jump back to a time before you made the adjustment, or you can keep multiple copies of your layer or document as a backup, but it's much better to use an adjustment layer. The great thing about adjustment layers is that they're nondestructive; your adjustments don't touch the underlying pixels of the image. So you can add, remove, and edit adjustment layers without worrying that you're committing to permanent changes. Fantastic stuff.
This chapter introduces you to adjustment layers, explains how they work, explores each of the adjustment layer types, and shows how you can really get the most out of these layers to produce great-looking images.
You also look at fill ...