A concept of color theory important in the graphic and visual arts, decorating, and design, among other fields, that attempts to define ways in which pleasing combinations of colors — color schemes — may be selected.

The solutions offered here for choosing harmonious colors for a scheme utilize a color wheel. There are many different color wheels, which can vary according to such things as whether we are describing pigments or light, additive or subtractive colors, etc. The color wheel I'll be using for demonstration, and the one with which most of us tend to be most familiar is that described by Johannes Itten in its twelve-color version, but the principle is the same for any color wheel.

```              R
RV   |   RO
\   |   /
V     \  |  /     O
.   \ | /   .
. \|/ .
BV- - - - - . - - - - -YO
. /|\ .
.   / | \   .
B     /  |  \     Y
/   |   \
BG   |   YG
G
```

# Basic Color Theory Refresher

In Itten's color space, red, yellow and blue are the three primary colors, arranged in an equilateral triangle:

```              R
/ \
/   \
/     \
/       \
/         \
/           \
/             \
/               \
B - - - - - - - - Y
```

Three secondary colors then are placed halfway between each of the primaries, the result of mixing equal amounts of the two primaries. Halfway between red and yellow is orange; halfway between yellow and blue is green; halfway between blue and red is violet (or purple, as you prefer; the exact names aren't terribly critical here):

```              R
. / \ .
.   /   \   .
V     /     \     O
.    /       \    .
.   /         \   .
.  /           \  .
. /             \ .
./               \.
B - - - - - - - - Y
.           .
.     .
G
```

Finally, six tertiary colorsare created by mixing each primary with the secondary to either side also are placed on the wheel, giving us red-orange, yellow-orange, yellow-green, blue-green, blue-violet, and red-violet:

```              R
RV . / \ . RO
.   /   \   .
V     /     \     O
.    /       \    .
.   /         \   .
BV .  /           \  . YO
. /             \ .
./               \.
B - - - - - - - - Y
.           .
BG .     . YG
G
```

# The Schemes

NOTE: White, grays and black can usually safely be used in any color scheme.

# Related schemes

Monochromatic
In a monochromatic color scheme, we choose just a single color, any color, from the wheel, and we use various values — these include shades (the color mixed with varying amounts of black), tones (the color mixed with varying shades of gray) and tints (the color mixed with varying amounts of white) — and intensities (i.e., the brightness or dullness) of that color. For example, a monochromatic color scheme based on red might include pink, red, and crimson. A monochromatic color scheme is easy to use, usually restful, but runs the risk of being monotonous.

```Monochromatic
(R)
RV       RO

V                 O

BV                      YO

B                 Y

BG       YG
G
```

Analogous
Analogous colors are those that lie next to each other on the color wheel, like yellow-green, green, and blue-green; or blue, blue-violet and violet. Most experts on design suggest choosing three or at most four analogous colors to develop a color scheme when using the analogous model, though it is possible to successfully make use of more. Of course, you may use different values and intensities of these colors. Analogous schemes offer a little more variety than monochromatic, but are still generally fairly restful and easy to use.

```Analogous
R
RV       RO

(V)                O
(
(
(BV)                     YO
(
(
(B)                Y

BG       YG
G
```

# Contrasting Schemes

A triad consists of any three colors equidistant from each other (and their tones, tints and shades). There are four possible triads on this color wheel. The primary colors of red, yellow, and blue together form one, as do the three secondaries of violet, orange and green, and there are two triads from among the tertiaries: red-violet, blue-green and yellow-orange; and red-orange, yellow-green, and blue-violet.

```Triad
R
RV       RO

(V)- - - - - - - -(O)
\               /
\             /
BV    \           /     YO
\         /
\       /
B     \     /     Y
\   /
BG  \ /  YG
(G)
```

Complementary
Complementary colors lie directly across from each other on the color wheel: red and green, or blue-green and red-orange, for example. Complementary color schemes offer more contrast than monochromatic or analagous schemes, and tend to draw attention to the color; it often is best to use them in unequal amounts, or with varying intensities, to create the most harmonious result.

```Complementary
R
RV       (RO)
/
V           /     O
/
/
BV          /           YO
/
/
B     /           Y
/
(BG)       YG
G
```

Split Complementary

Pure complementary schemes provide you with only two colors and their shades and tints. There are other types of complementary schemes that provide a wider range of color, and are less boldly contrasting than pure complements. One of these is the split complement, which is comprised of one color along with the two colors on either side of its true complement. For example, the split complements of orange would be blue-violet and blue-green; the split-complements of green would be red-violet and red-orange.

```Split Complementary
R
(RV)     (RO)
\     /
V      \   /      O
\ /
|
BV          |           YO
|
|
B        |        Y
|
BG   |   YG
(G)
```

# Discordant Schemes

These can take the most skill to use successfully, but they provide the greatest range of colors and can create rich and dramatic results.

Alternate Complement
Another complementary scheme is the alternate complement, which provides four colors. It consists of a triad plus the true complement of one of them. For example, to the triad above of orange, violet and green, we could add orange's complement, blue.

```Alternate Complement
R
RV       RO

(V)- - - - - - - -(O)
\             . /
\         .   /
BV    \     .     /     YO
\ .       /
. \       /
(B)    \     /     Y
\   /
BG  \ /  YG
(G)
```

Double Complement
The double complement is a complementary scheme that combines two sets of complements, like blue, orange, red and green; or red-violet, red-orange, yellow-green and blue-green.

```Double Complement
R
(RV)     (RO)
\       /
V     \     /     O
\   /
\ /
BV          X           YO
/ \
/   \
B     /     \     Y
/       \
(BG)     (YG)
G
```

The tetrad is a special form of double complement consisting of four colors evenly spaced around the wheel, like red, yellow-orange, green, and blue-violet. There are three possible tetradic schemes, each one comprised of one primary, one secondary, and two tertiaries.

```Tetrad
(R)
RV   |   RO
|
V        |        O
|
|
(BV) - - - - + - - - - (YO)
|
|
B        |        Y
|
BG   |   YG
(G)
```