Only Web Colors
This version of PhotoShop is equipped with the ability to specify web safe colors in the color picker. The same color picker is located in ImageReady.
Working in PhotoShop, look at the tool bar and click on the foreground color icon. This will open the color picker (pages 90 and 91). After you check the box that specifies "only web colors", your color picker will look like the one on the top of page 91.
In the color picker panel, the H button stands for Hue, the actual pitch of the color selected. The S stands for Saturation or depth of color and the B stands for Brightness. Experiment with each of the settings as in steps 2, 3, and 4 to see the colors you can make with this adjustment. When you have finished, proceed to the next lesson on snapping to web colors and setting the color palettes.