As the cover of the book The Art of Color, by Johannes Itten, suggests, colors can be pretty tricky to manage. Once you get beyond the basic lessons of the color wheel, you still have to juggle how colors relate to one another, and context is everything. Color theory is all about physics, psychology, and perception, so it's no wonder things get complicated fast! This is why I personally think color is easier to manage, and appreciate, when you limit yourself to a handful of hues. Even one!
Now, I recognize a limited palette isn't for everyone. But I do think it's a great way of isolating color and thinking about it. I'm also a big advocate of learning from found color schemes. Don't be afraid to appropriate a color scheme for your own art. Vintage packaging is a great source for color because of the limited printing technologies designers had to work with. This scheme is based on the two complimentary colors red and green, as it was a 2-color print job.
Background artists are also masters of color. Oftentimes, they need to work in a fairly limited palette so as not to combat with the characters' colors in the foreground. Bill Wray has some amazing background art from Samurai Jack on his blog. Below is an analogous color scheme of plums, purples, and pinks. Note that there is plenty of room for accents in a limited palette.
If your colors are limited and related, they end up being easier to sort out. And I tend to think they're more pleasant on the eyes. Once you start cluttering up your image with too much color, it can start to look like a coloring book. Colors begin to claim territory on the page, and they become isolated from one another. Color should be about harmony, unless you are purposely trying to create an unsettling image. Here are a handful of artists I like who are using a limited palette extremely well.
Once you get a handle on juggling one or two colors, adding a third or fourth becomes a lot easier. I should also note that when I say color, I really mean a family of hues...not a single swatch. There will be more to come on true color theory, but I thought this would be a good starter discussion. Color theory becomes essential when you want to know why one color scheme works better than another, or how to fix something when it doesn't work. If you're feeling a bit rusty (or curious!), I just happened upon a pretty good online color theory resource at worqx.com:
--> Color Theory Tutorial (a rich man's guide)
But it can get abstract, quickly. In a future post, I hope we can break down what we think are the most important lessons of color theory. Until then, happy coloring!