However, we are working with complementary colors which, I believe, Nonnie has said she doesn't like.
Which all goes to show: While some of this is science, a lot of it is art, and most of it is simply personal preference.
But we move on.
Today we're doing two color harmonies because otherwise we'll never get through the dang book.
Opposite Colors
Colors opposite one another on the color wheel are called complementary.When you go opposite, you will always have one cool and one warm color, which automatically creates balance, as well as excitement. Putting two colors side-by-side also intensifies both of those colors. If you want to tone that effect down a bit, you can simply add a neutral (such as white, black, gray, etc.) to settle things. You can also use tints and shades, adding white or adding black to the main hue, to create even more interest but also settle things down a bit. Using each color in its most pure form will have the most dramatic effect.
Color Magic for Quilters has some interesting tips about how to determine the appropriate amount of each that I won't go into here since my goal isn't to render their book unnecessary. I encourage you to get the book for yourself--it's got great information in it!
Play Time--Complementary
I went for purple and yellow. I do like this combination, although if I were to turn this into a quilt, I'd definitely be using some tints and shades to make it a lot more interesting.By the way, that darker fabric really is purple. Between the lighting and using my phone camera it came out a whole lot more blue. I tried doing some color adjusting to bring it back to its actual color but was only partially successful.
Here's green and magenta out of my stash. Although the colors work together, I don't like this combination of fabrics so probably wouldn't use it in a quilt, unless there was a whole lot else going on and one or both of these was smaller pieces.
I decided to get into my crosswoven fabric collection to see how that works in terms of the color wheel. I bought these at the Mid-Atlantic Quilt Festival from a wonderful vendor carrying fabrics from all over the world. These are from Indonesia.
If you're not familiar with crosswoven fabric, it's fabric woven from one color thread in the warp and a different color thread in the weft. The finished result is primarily one color, but you can see that other color when you hold it just the right way. Super cool.
Here's green and magenta. (Note that the green is crosswoven with blue, so it depends on the light which color you get more strongly. The magenta is crosswoven with green.)
Moving on...
Opposite Colors with an Accent
Our second color harmony for the day is kicking it up a notch: take those two complementary colors and add an accent. Any accent. You have a few colors to choose from when you're deciding on your accent.
Generally, that accent is most effective if it's at least one color removed around the color wheel from one of your two complementary colors. In fact, Color Magic for Quilters refers to this as "the preferred accent." Choose your complementary colors, then move two colors away to either side of one of them for the accent. Note that this technically gives you four different options of colors to use as the accent. However, as in everything, there's no hard-and-fast rule about that. Do what feels good!
Accents give the whole thing just a little more jazz, a little more excitement and interest. Not to say, however, that a straight-up complementary can't be really interesting! But if you're working on a complementary scheme and it's just not flipping your switch, try adding an accent.
Play Time--Complementary with Accent
Going back to my original complementary pair of purple and yellow, one accent I might choose would be green. 
I do like this combination, although if I were to make this a quilt I wouldn't use these three fabrics. It needs contrast of print in there to make it really sing. But the purple-yellow-green thing feels like a garden to me.
Back to the crosswovens, just 'cause they're purdy n' I love them.Yellow-green, red-violet, blue-violet. (I have to stretch the color wheel a bit with the crosswovens since they're not distinctly one color or the other!)
Blue, yellow-orange, purple-ish. I do like this set of three and could see it working. The crosswovens have sort of a funky Amish thing going on.
Back to my original combination of magenta and green using the Ives wheel, I picked up yellow for an accent. 
If only I wanted to make a nice spring quilt right now, and didn't have fifty other projects in my head that I'd like to do first!
Your turn! As usual, link up your own blog posts showing us how you might approach these two color harmonies: opposite and opposite-with-an-accent, aka complementary and complementary-with-an-accent.
