I was in the movie theater recently, and in a moment of too little or too much drama, turned my eye to the screen itself; and so started thinking about rectangles

It's definitely more than two-to-one; I estimated it at 2.25:1. That width is what sparked my interest.

If 35mm photo film is getting a little too wide for the single-person image, this cinema proportion is suited only for crowds and vast African landscapes.

But movies, and the movie I was watching, are in the great majority concerned with humanity, not places. They spend an inordinate amount of time on close-ups of one person, and most of the remainder on two people interacting (and even that leaves a lot of room left over).

So I was suddenly struck by how the director was solving the ongoing problem of how to frame the story when the space at hand was almost always unsuited to it.

You might center the speaker against the background, but in fact this never happens. What happens instead is a constant exercise in off-centering to produce the best effect.

One speaker almost always falls about a third of the way across the screen (a most Pythagorean ratio). To create a sense of expectation of something arriving from off-screen, the distance shifts to about one-fourth, deliberately opening room that isn't filled.

Only when the effect of great space and loneliness is desired does the figure move closer to the edge of the visual rectangle, but never once did it actually move all the way to the visual edge.

Even when two figures are on-screen, they are not balanced; they're off-center in a way that preserves visual tension, and the main speaker is always the one closer to the center. In short, I spent a solid hour just watching how the movie moved in the space it had.

Now, much of these are simple compositional rules of thumb that photographers or cinematographers recite in their sleep.

But I've never been aware of it as a dynamic, moment-to-moment process, a kind of choreography of avoiding static symmetry and overbalanced space at every moment as the action changes.

It's a process that would never arise if the screen size actually fit the story being told, the way the portrait neatly fills the shorter rectangle.

It's the very unsuitability of the wide screen that creates the problem, and the extra layer of interest that is unintentionally created by having to solve it every few seconds. (Imagine, if you will, having to write if every paragraph had to have the same number of words in it—and too many words, most of the time.)

This puts the moving picture closer to music, which is also an ongoing choice of ratios (Pythagoras again) evolving in time.

It also leaves plenty of questions open for how the choice of placement varies in response to the narrative; for, like music, such choices can be harmonious or discordant, satisfying or disturbing, tense or resolved.