Strictly speaking, silhouettes represent an abstraction of the subject - details sink into darkness, only the outline shape remains. In the case of a human silhouette, our brain has learned to interpret much information from the figure's posture. Often we can tell what gender the figure is and what mood it is in.

The more information we can glean from the figure, the more interesting we find it. 

 

"I like to work with silhouettes, by reducing them to your outline the protagonist becomes a graphic form. The tension between the urban landscape and the people acting in it becomes clearer."