Red on a black background gives a glowing effect. A white background dulls the red, and red merges into the color orange with a clashing effect. The best color to pair with red depends on what effect is desired.
Color harmony is important to humans as it is pleasing to the eye. Color is the first thing a person sees; it is a type of visual communication. Colors can be used to attract or send signals. The color wheel is an accepted set of colors that are organized in a particular order. The use of a this wheel helps to create harmonious or clashing effects depending on what is needed.