How Do Layers Work?

At first glance, layers might seem complex, but the idea behind them is rather simple. You isolate different parts of your image onto independent layers (Figure 3.1). These layers act as if they are separate documents stacked one on top of the other. By putting each image on its own layer, you can freely change your document's look and layout without committing to the changes. If you paint, apply a filter, or make an adjustment, it affects only the layer on which you're working. If you get into a snarl over a particularly troublesome layer, you can throw it away and start over. The rest of your document will remain untouched.

You can make the layers relate to each other in interesting ways, such as by poking holes in them to reveal an underlying image. I'll show you some great techniques using this concept in Chapter 13, “Enhancement,” and Chapter 15 “Collage.”

But first, you need to pick up on the basics—the foundations—of layers. If you've used layers for a while, you might find some of this chapter a bit too basic. On the other hand, you might find some juicy new tidbits.