Color: Color Wheel
By Rio

Wheel with White BackgroundBasics
The color wheel is comprised of main colors (on the outer ring): red, purple, blue, green, yellow, and orange. The inner ring are pastel versions of the main colors. If there was a third outer ring, it would be a darker shade.

The colors orange, red, and yellow are known as the warm colors. These colors are bright, cheerful, and are associated with anything hot which is why they are aptly called warm colors. 

Purple, blue, and green, on the other hand are the cool colors. These three colors are are often used in shadows among other things which is why they are called cool colors.

Terms
Some useful terms that you should familiarize yourself with:

Hue
- A pure color; the color itself (red, yellow, blue, etc.)

Intensity - refers to the brightness of a color. In order to lower a colors intensity(dull down), add a small amount of its complement; its opposite color(more about complements later). For example, to dull down red, add a bit of green. If equal amounts of red and green are mixed, the color becomes brown not a dulled down red.

Value - refers to the lightness or darkness of a color. For example, to lighten a color add white.

Primary Colors - red, yellow, and blue. They are the basic colors that make up all the other colors of the color wheel. For example, if you mix red and yellow - you get the secondary color: orange. Mix red and blue - you get purple. Mix blue and yellow- you get green. And from there you can create tertiary colors like turquoise (a blue green color) or fuschia (a red purple color).

Secondary Colors - orange, violet, and green. These are made mixing any of the primary colors as explained above.

Tertiary Colors - Colors made by mixing a primary and its secondary color.

Neutral Colors - when equal amounts of two complementary colors are used, a neutral grey or brown is made.

Wheel with Black BackgroundUsing the Colors
Colors adjacent to each other are called Analogous Colors. These colors are beside each other in the color wheel such as red and orange, green and yellow, green and blue, blue and purple, etc.

Colors across from each other are called Complementary Colors. Colors such as purple and yellow, green and red (x-mas colors!), and blue and orange can be matched together.

If you try to match colors that are not Complementary or Analogous, they do not fit together as well. Try to stick to using complimentary and analogous colors as much as possible.

If you want to use other color coordination besides the one's mentioned, you may do so but you might have to take up a bit of time mixing and matching.

The Other Color Wheel: CMY
The color wheel described above is the traditional color wheel where the main colors are grouped based on the classic methods of mixing color through paints. These are RGB (red, green, blue). With the advant of computers and printing, a new color wheel emerged called CMY (cyan, magenta, yellow) color wheel as seen on the right.

So, which one should you use? Either one is usable though most people tend to favor RGB in general over CMY.

Tips
1. When using color, you have to consider other colors as well. For example, if you use a white background as the colorwheel above right, the colors in the wheel look brighter whereas the colors with the black background above look darker. Colors take on the "effect" of the color surrounding it!

Color balance example 2. When you create a character, your choice of color will make the character look either a good guy or a bad guy. Good guys usually have "lighter" color clothing as opposed to bad guys which have "darker" shades of color. This does not mean that you have to give your good guy character's all pastel colors -- what it means, for example, is that if a good guy has a blue shirt then as a bad guy the shirt color will be blue also but in a darker shade.

3. Look at the composition of the colors in a picture. Try to achieve balance. Take this example here to the left. When I colored this guy, the orange stood out a lot. I mean a lot!! To dull down the orange I used a dark blue background - orange's complementary color. That is balance. Try to consider it when you color your drawings or other images.