In the 1950s, the psychologist J.J. Gibson outlined a number of cues to depth perception. A few rely on our binocular vision and therefore do not apply to 2-dimensional drawings and paintings. Others, however, are psychological rather than physiological in nature. As such, these depth cues are pictorial in nature and are applicable to drawing and painting on a 2-dimensional surface. In the following, I try to use simple terms and snippets of my own drawings and photographs to illustrate each of the depth cues that I consider to be relevant to drawing on location.

Convergence of parallels: This is a key characteristic of linear perspective in which parallel lines appear to converge as they recede into the distance. Despite the usefulness of the other depth cues, linear perspective remains the structural scaffolding upon which to build a sense of spatial depth on the page.

Overlap: Near objects overlap or partially block the view of objects farther away. Locating effective overlaps can be useful in selecting a viewpoint and composing a drawing.

Position relative to the horizon: Objects below our eye level rise toward the horizon as they recede; objects above our eye level descend toward the horizon as they recede.

Relative size: Objects known or assumed to be of similar size appear to shrink in size with distance from the observer.

Texture gradient: Surface texture appears to get finer and smoother with distance from the observer.

Shading and shadows: Contrasts in light and dark can convey the shape, form and depth of objects.

Aerial perspective: Particles in the atmosphere affects the color and visual acuity of objects at varying distances from the observer; distant objects appear grayer or bluer and less distinct than nearer objects.

As we can see, scenes more often than not comprise a number of these depth cues operating simultaneously. Seeing how these depth cues occur in our real-life perception can aid our understanding of why things appear as they do, counter to what we know of the things we draw, which are often in conflict.

Along with a few fellow architect-volunteers from the community service committee of the AIA Young Architects Forum, I met this morning with a group of middle schoolers attending the Northwest School Summer Camp. Our task was to introduce some basic drawing concepts to the young students. My topic was negative space, a concept that is somewhat difficult to grasp, especially when translating the in-between spaces that we see in real life into the two-dimensional shapes we draw on paper. After the session, I remembered an animation that I had created a while back when I was conceiving of a ebook on drawing. Here is an unedited version of Seeing Shapes.

SeeingShapes

Keep in mind that it is often easier to see shapes in a photograph and more difficult to see them when drawing on location from direct observation.

With the rise of digital photography color has become pervasive, unlike the film era where black-and-white photography was prized for its confident and raw visual style. In the field of sketching, too, color sketches are often seen as richer and communicating more information than monochrome drawings, which many consider to be primitive and lacking emotion. Yet, utilizing a range of strokes, black-and-white sketches can express a wider range of feelings than one might expect…

from light and airy…

to dark and heavy…

from descriptive…

to illusory…