The phrase "layering and separation" is applicable to images specifically, because the colors of images need to be layered and separated in order for the image or design to be effective. In the example of the images of the figure doing the marshalling signals, the lights are bright orange, whereas the person is gray, which creates two different layers, helping the lights to stand out from the man. The color distinction also separates the man from the lights, as well. "Layering and separating" essential describes the way that certain parts of images stand out from other parts of the same image. Color, shape, and design are crucial for the layering and separation to occur. The following quote outlines the importance of layering:
"An omnipresent, yet subtle, design issue is involved: the various elements collected together on flatland interact, creating non-information patterns and texture simply through their combined presence" (Tufte 53).