Negative on positive relationships are just as strong and clear as pos-on-neg ones, although with different effect and feeling.  A neg-on-pos foreground shape will jump forward from its darker background in a way that is often more effective in creating an illusion of depth than a pos-on-neg relationship.  Fig. 30b shows a simple example of the most basic kind of neg-on-pos relationship, where the foreground character is done entirely in soft colors, making it easy for it to pop forward from the deeper background.  Dark and medium blues are used in the background to push the fish forward; enough color is used in the background to give it a feeling of depth, while enough skin is pulled through the background to give it some motion and avoid the dense “bruise effect”.  Instead of lining the details inside the fish in black, which would have compromised the strong neg-on-pos relationship, these details were outlined with color, then reinforced using a liner and deeper color after most of the coloring was finished.  Selective use of black in the eye and mouth makes these features pop out.

In Fig. 30c we have a clear and simple example of neg-on-pos, with heavy shadows pushing the hook forward and making it clearly readable; details within this shape are kept simple and light in order to not compete with the strength of its neg-on-pos relationship.  For added readability, a bold black outline ensures the clarity in any areas where the background isn’t substantially darker than the foreground.