Would you hire a carpenter who didn't know anything about wood? Pixels are the wood of Photoshop; they're the material you use to construct your images. Without a firm understanding of the strengths as well as the weaknesses of your material, you won't get very far with this power tool of a program.
In this chapter, we've focused on the inherent attributes of pixel-based images, but one inherent attribute that we referred to only in passing is also one of the major sources of frustration to anyone who works with digital images. That attribute is color ambiguity: If you ask 100 people to visualize "red" you'll likely come up with 100 different colors. Likewise, if you display the same image on 100 monitors you may well end up with 100 different images unless you take steps to prevent that outcome. But before we examine the solution to the problem in Chapter 5, Color Settings, we need to tell you a bit about the nature of color itself, and go into a little more detail on the sometimes-mysterious relationship between color and numbers.