GradationGradation refers to a way of combining elements by using a series of gradual changes. For example, a gradual change of small shapes to larger shapes, or a gradual change of a dark value to a light value, would be gradation.
E l e m e n t sColor | Value | Line | Texture | Shape | Form | Space
P r i n c i p a l sBalance | Emphasis | Harmony | Variety | Gradation Movement | Rhythm | Proportion
T e r m sLook for more terms here