Photography relies hugely on the simple compositional device of bringing two or more subjects together in the frame. I say hugely because of our innate tendency to assume a relationship between things seen side by side. At the very least, juxtaposition brings two things to our attention at the same time, and as soon as the viewer starts to wonder why the photographer chose that viewpoint, and if the juxtaposition was intentional, this sets off a train of thought.

There are two sources for juxtaposition, although one inevitably triggers effects on the other, and these are the content and the graphics. Perhaps "motives" might be a better term than "sources," because in the first case the initiative comes from subject, and in the second the eye-line straight out from inspiration more often comes from chance appearances (as in, for example, the boy to the viewer makes it the strongest focus of attention. Faces always carry-reflection of one thing in a window through which can also be seen a second subject). The two, content and graphics, are never completely separated.

The amount of deliberation can vary enormously, from a planned expedition to find a way of juxtaposing two subjects, to spur-of-the-moment coincidences, and if the final image is the only thing that a viewer sees, in itself it is not at all a reliable indicator. The examples here, described in more detail, cover this range. The reflection shot of the mountains was planned days in advance, while the cellphone advertisement...