YOU DON’T HAVE TO DO ANYTHING TO AN ADJUSTMENT LAYER TO MAKE IT USEFUL
Okay, I’m going to get a little techie on you here. But trust me, I’m doing it for your own good. I’m getting techie because it’ll help you be more creative in the long run—you’ll see why. Many times, when you’re working on a layered document you’ll duplicate a layer and change its blend mode to something like Multiply or Screen just like we did in Chapter 2. Then you’ll selectively erase part of that duplicate layer (or better yet, use layer masks, which we’ll talk more about in the next chapter). Here’s the thing: the second you duplicate that layer, your image is taking up twice as much space on your computer as it did before.