Harmony is the accordant arrangement of colors. Color harmonies, like music, are beautiful. Colors that are in harmony must contain at least one common color. For example, if red, blue and green have had orange mixed in to each of them, these colors will appear related, and will be in harmony with each other. Colors need at least one common color in them to be in harmony, but often they share more. For example if red, blue, and green all have a small amount of red, blue, and green in them, they also will be in harmony.