You've learned a lot so far about the way the painting and editing tools function in Photoshop. It would be wrong to just dump all that information on you without giving you some context for it. Now you'll learn how to apply what you know about the brush-based tools to some sophisticated painting techniques.
Okay, admittedly, this one doesn't sound so sophisticated, but you'd be surprised how much you can do with this deceptively simple technique.
There are a couple of different ways to draw straight lines with the brush tools in Photoshop. To connect two points with a straight line, click where the line should start, then hold down the Shift key and click where the line should end. A perfectly straight line joins the two places where you clicked. Continue Shift+clicking to draw additional lines from each point to the next. All the characteristics of the brush you are using are respected — Opacity, Flow, Airbrush, and even all the dynamic settings.
The other way to draw straight lines is by holding down the Shift key before you start painting — this constrains your brush strokes to horizontal or vertical lines. Using combinations of these techniques with varying brush tips can yield surprisingly complex results, as shown in Figure 19.26.
Once you've got your ...