In his recent post, Robert Jackson mentions the psychological resonance that double exposures can have: as with classical surrealist disjunctive imagery, the viewer can’t help trying to relate the component images.
The snapshots shown above are simpler. Though what I am about to say is far from completely true of all my examples, ideally this class of picture has no psychological resonance at all, no mystery, nothing to make you think, no thematic content—none of that stuff that other kinds of photos have. And they’re not freaky; they don’t bomb you with strangeness. So what’s left? I chose them because they’re little more than accidental compositions. I tried to get rid of everything else. If they have a subject, we’d have to say they’re about accident itself—about what’s at the heart of the snapshot. These are snapshots purged of everything irrelevant, stripped down to what is snapshottiest. From a certain point of view I think they are about as pure as snapshots can be.
Though so mundane that they are essentially empty, at the same time they are as statistically improbable as any good snapshot. Cases differ, but in a general sort of way we might say that what is most fortunate in a good double exposure is the choice of the two superimposed images; their precise registration is less important. But an accidental composition is all about precision. A fraction of a millimeter’s change in the position of the elements could very often destroy it.