Are you happy with your quilts? Or do you look at the finished top and wonder why your beautiful fabrics made such a boring quilt?
The most common problem is a lack of contrast. It isn't enough to choose two colors from opposite sides of the color wheel. You also have to consider the value of those colors. Value is a way of measuring the lightness and darkness of a color. A high value is very bright or light. White is the epitome of high value while black is the essence of low value. Those are the easy ones.
In between, you have every variation of color and value. You also have pure colors, tints, shades and tones. Tints are color with white added, shades are color with gray and tones are color with black. It is sometimes hard to tell the difference between a shade and a tone, and I wouldn't lose a moment's sleep over it. The point is to see how colors look next to each other.
If you pick four blue fabrics and each is a different value, you can make a beautiful quilt. If two of them are the same value, some parts of your quilt will be mushy. That is my own term for what happens when you can't tell where one piece stops and the next one begins. If you were making a landscape and using many different fabrics for the leaves, mushy edges would be desirable.
Tip: How can you tell if you have contrast? You can look at the arrangement through a piece of red plastic, held up against your eye. That will show you most fabrics in shades of gray. This method is not foolproof and both reds and greens may read darker through the filter. If you can find a gray plastic, that will be more accurate.
If you have a digital camera, take a photo and look at your fabrics in grayscale. Most graphics software has this option. If you do not have any graphics software, print the photo out in grayscale on your printer.
When you are constructing a star in star, you want that center star to stand out. There should be a dramatic shift in value between the main star and the star inside it. In the three blocks below, you can see what happens. On the left, the large red areas in the print match the large star color almost exactly. The result is a complete loss of definition of the small star edges. The center star uses a green print with tiny red flowers. While they, too, match the large star, they are so small that you do not lose the small star lines. The print in the third block has a brighter red, mixed with different values of green and cream.
Think of it this way. A high value color is 5'-6' tall. A medium is anywhere from 3'-4 tall. A light is 1'-2' feet tall. If I arrange a group of people together who are all between 3' and 4', a casual glance will perceive them as all roughly the same size. It would be hard to pick one out of the crowd. Suppose I add a single 1' tall person and a single 6' tall person. They will stand out and look like misfits.
Now think about every graduation picture you ever saw or the mass of people in a big chorus all standing together. The people are arranged by height for a reason. It evens out the differences if you have them stand in ascending and descending sizes, moving smoothly from 1-1-2-2-3-3-4-4-5-6-6-5-5-4-3-3-2-1. In a group picture, you want homogenous.
If you did this with colored fabrics, you would be creating a value gradation, moving from the high intensity to the low and back again. Around the World quilts are spectacular when the concentric rings are arranged in value gradations. It works for that quilt because everything in the quilt is striving for a single impact. Lone Star quilts also use gradations, either in color or value. Each successive round changes and creates the feeling that the star is vibrating.
Remember how that single 1' tall person looked odd? When you introduce an accent to your quilt, use it more than once. You do not have to use an amount that is equal to the other colors or values in your quilt, but you want to use it at least three times. Experts recommend that you stick with odd numbers of pieces. I think that depends on what you are making. Abstracts and landscapes have different design requirements than traditional repeating block patterns. When working out your fabric choices, try not to be rigid. Pull out more fabrics than you think you will need and audition any that look like they have something to offer your quilt.