Color Schemes

Complementary colors are opposite colors on
the color wheel. They create a contrast in between
them. A football team which uses complementary
colors as a logo are for example the Denver broncos,
with blue and orange.
All colors are based on three ground colors.
Red, blue and yellow. For example red mixed with
yellow creates orange. Yellow and blue creates
green, and blue mixed with red creates purple.

In addition to the 12 basic colors on the
color wheel, you can add 100 more, if you regard
the different color values. White added with a color
creates a lighter color tone, also called tint. Black
added with a color creates a darker color tone,
named as shade. The more shader a color is, the more
it tends to be black. The more tinter a color is, the
more it tends to be white.
There are also neutral colors, which are considered,
to contain equal parts of the three basic colors. For
example black, white, gray and sometimes brown,
are neutral colors.

Color Schemes for websites:

Analogous colors are adjacent on the color wheel.
They are in between two of the three basic colors,
which are next to each other. It is used for example
at http://ard.de/

Complementary colors are opposite on the color
wheel. They complement each other with a
high contrast. An example is
http://www.denverbroncos.com/

Monochromatic colors are colors of the same kind,
just shaded or tinted. For example
http://www.msn.com/