In the real world, when you place a second brush full of paint over paint that's already there, different things happen, depending on the color of the paint you're applying—how opaque it is, whether the first layer is wet or dry, and so on. In Photoshop, you can control all these factors by applying what's called blending modes. You'll find them on a pop-up menu in the Tool Options bar, as shown in Figure 8.12. Blending modes apply to all tools that can draw or paint, including the Pencil, Clone Stamp, and Gradient tools, as well as the more obvious ones. As you can see, there are quite a few modes. Take a quick look at the blending modes and how they work.