Color is a valuable material. Don’t use it merely because it is available. Don’t decorate with it. Use it to shape the message by explaining, emphasizing, guiding.
Assign color deliberately. Decide what you want the viewer to understand first, then use color to make it obvious. If you rely on decoration and entertainment value for readership, you are wasting your (and your readers’) time. Color, like any other contrast, must be used as a tool for describing relative importance.
Avoid coloring extraneous elements like lines, bullets, and decorative elements unless there is a very good reason for it.
Link separate elements by using the same color. Shared color relates them.
Use the same color for all signals and signposts. Making them immediately recognizable is a service to the reader.
Keep color choices simple. Develop a limited color palette for each paper or Web publication. Your palette should dictate color choice if properly conceived.
The larger the area, the lighter the tint should be. Large areas should be conservatively colored to avoid overwhelming the message.
The smaller the area, therefore, the stronger the color can be. Accents should be bright, but they must be small or they cease to be accents.
Colors are always perceived in relationship with other colors. Light is only light when something darker is nearby. Warm colors appear to be in front, cooler colors appear to be behind. So assign a warm tone of a color to an element, say, a headline, that appears in front. To strengthen the illusion of depth, assign a cool tone of a color to the element in back.
Colored type must be bolder or larger. Any color has lower contrast than black on white.
Be sure there is at least a 30% tonal contrast between type and its background. If in doubt, increase the contrast. END
Alexander W White 