Shared Boundaries

OK, so this photo isn't going to win any awards, but I have posted it here because it illustrates an interesting compositional technique. If you haven't worked it out already, its a set of railings and the shadows cast by them. When framing this composition I deliberately made the shadow and the bottom of the railing share the same boundary. When you look at that central line, the perspective has collapsed and the image seems to flip-flop between having the base of the railing above the shadow to having it below.

Contributing to this illusion is the way in which you interpret a scene. Pyschologists have concepts of leveling and sharpening. If you are a leveller, you tend to simplify your experiences, you tend not to notice differences. If you are a sharpener you are a little more analytical, you will notice things that are out of place. In relation to this image, if you are a leveller, you will tend to treat the shadows on the base of the railing as a continuation of the shadow on the ground. enhancing the collapse of perspective.

Another thing that lends itself make a little confusion is that there is a figure ground relationship between the shadow and the ground. Because the lit areas have a clear boundary, they tend to be seen as a figure making them pop-up just a little.

Even though I know exactly what I'm looking at, I still experience some visual confusion. I'll be looking for more opportunities to use shared boundaries for abstracts in the future but hopefully prettier ones than this.