Use Value Contrast
To Define Shapes
There is an ancient saying handed down through the ages from quilter to quilter; you've probably already heard it a dozen times; But that's not going to stop me from repeating it one more time:
Value does all the work; color gets all the glory.
Too often quilters only pay attention to the color hue of the fabrics they choose and forget to consider the color value. They don't realize that choosing darks, or lights, or mediums is often more important than choosing colors.
All the colors are dark. That makes it hard to see the Ohio Star. It's late at night and there's almost no light and this is what you see. Almost nothing, because there is very little value contrast.
All the colors are light. The first example was like being in the dark; there wasn't enough light to create contrast. This time it's like staring past a strong light; there's too much light and very little contrast.
There's not enough contrast between the medium values of the Ohio Star and the medium background.
How much contrast you use depends on how much attention you want to draw to a block. If you want a block to stand out, increase the contrast. If you want it to fade into the background, reduce the contrast.
See also: Use Value Contrast To Focus Attention