Light Leak

Light gets into the camera body where it should not, and fogs the film before it is ever exposed properly. The frame carries a streak of colour that has nothing to do with the scene.

It reads as an accident, and that is its value. A leak says this footage was shot on a real camera that was not in perfect condition, which is why the look attaches so easily to memory and to home movies.

The cause is a failed seal. A perished door gasket, a loose back, a cassette handled in daylight, and light reaches the strip through the gap instead of through the lens.

Because the gap is at the edge of the camera body, the fog enters from the edge of the frame and falls off inward. It is usually warm, because the light travels through the camera body and picks up its colour on the way.

It does not respect the shutter. A leak can run across several frames and change as the camera moves, which is why it flickers and drifts rather than sitting still.

Use it for footage meant to read as found, as old, or as shot on something unreliable. It also works to mark a transition, because the fog can wash the frame between two moments.

Avoid it in anything that has to look controlled. A leak announces that the equipment failed, which is the wrong note for a product shot or a clean interview.

Lens flare comes through the lens, so it obeys the geometry of the frame and the source. Ghosts sit on the line from the light through the centre of the picture.

A light leak comes through the body, so it enters from the edge and ignores where the sun is. The test is stated in the entry itself: a centred glow is a flare, and a leak comes from the edge.

The model puts a soft glow in the middle of the frame, which is a flare. Say the streak bleeds in from a named edge, left, right, top or bottom.

The second failure is a leak that sits perfectly still. Ask for it to drift and change across the shot, because a fixed shape reads as an overlay.