The Direction of Light

    You and I have a lot in common. Among these commonalities is our sense of the defining effects of natural light. For a long time we have perceived light as falling upon us from above.  This is natural because, daylight cascades down upon us illuminating the top side and leaving the under side shadowed.   We are diurnal critters, daylight operators; we prefer to hunt, gather, and live in the daylight, in an environment which is more fully revealed to us ( our color detection and image detection works best in daylight) as opposed to the dark.  Our brains are wired to think of light as a defining force falling from above. This helps explain our response to examples 1 and 2.  Because we perceive light as falling we see light as revealing convex ( bulging little bumps)or concave(hollows) circles.  Our mind makes the circles concave or convex depending on the shape of the shadow.  If I flip example #1 horizontally suddenly, all the concave circles get reversed to become bulging convex circles and vice versa. They traded places not because , the illustration was altered. It wasn’t. It’s the same information just flipped horizontally.  Our predilection to thinking of light as a falling descriptive phenomena reversed  the concave/convex identity of the circles.    If you are a painter, like the Italian middle 19th century painter represented here (see example #3, a street scene by Giuseppe Abbati, I believe) you knew how to place shadows under the window ledges  to make them protrude from the wall and how to place shadows at the top of the windows to indicate the window’s indentation in the wall.  This works because, we have that universal predisposition to see daylight as a descriptive agent falling from above.   In my other example, I painted a night, street scene.  The colors are not typical of daylight; they are artificial and hot. They define the subject from the side or from below not, as natural falling daylight does.  The sensation is more discomforting, more alien than the 19th century Italian street scene.   We miss the color-giving daylight and its familiar forms.     The last example shows falling daylight but, in an interior. I still use the  light to describe forms as it falls from above but, it falls more specifically through  the oculus in the dome in the Pantheon in Rome. The large spectral Buddha is lit from above but, the other figures are silhouetted. This odd combination of illumination signals the brain that the lighting is not out-of-doors but rather, in some confined place.  Light determines not just the shapes but also the context.