An accent color would be the color across from one of the top three choices. In this case we used blue, because it was opposite orange. So the quilt would consist of red-orange, blue and green. 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.