Some links about using color:

http://www.worqx.com/color/itten.htm (saturation and hues)

Color Matters:
http://www.colormatters.com/symbolism.html

Using color can help you do the following:

• highlight a point

• tell the reader where to look first

• group related items together

• establish hierarchies of importance

• evoke an emotional response

• make your communication look more polished and attractive

Some guidelines for using color:

• use color for clarity and emphasis and not decoration

• use a color scheme, not just a single colors

• use bright colors to focus your readers' attention

• use contrasting colors to create emphasis

• use warm intense colors to make items "advance" toward the reader

• for easier reading, use a high contrast between text and background

• use the associations that colors already have for your readers

• be consistent to help readers establish patterns of meaning

• stick to a few colors