There are three color characteristics to be aware of when choosing the right colors for your quilts. They are value, visual temperature and intensity. Value is the relative darkness or lightness of a color. Value is best used for establishing depth in a block. For example, by putting a red against a slightly darker or lighter red you can create an illusion of depth and movement.
Visual temperature is when a color is either warm or cool.
Typically, warm colors will advance in a block, or move toward you, while the cool colors tend to recede into a quilt block. We also seem to crave more cool colors than warm because warm colors can be very aggressive and overpowering. Some of the most eye-catching and appealing quilts use warm colors, however. Intensity is the brilliance of the color. The pure colors such as red are more intense than the muted low intensity yellow-green.