Color Icons

Don't design a color icon that's substantially different from your black-and-white icon. When you add color to an icon, it's best to leave
the one-pixel black outline and other black lines that form the icon, and fill the icon in with color. Coloring or graying the icon's outline makes the icon appear less distinct on the desktop. Remember that the user can change the background color of the desktop as well as its pattern, so your icon may not be displayed against the background on which you designed it. If you use ResEdit version 2.1 or later to create your icons, it provides a way to look
at your icon against different backgrounds to see whether your design is effective in various environments such as black-and-white displays or color displays of different bit depths. Figure 8-21 shows how icons with a black border look on a gray background.

Figure 8-21 Icons with a black outline

Figure 8-22 demonstrates how an icon appears less distinct from its background without the strong black border.

Figure 8-22 Icons without a black outline