Light Leak

A light leak is an opening, gap, or weakened seal in a camera body or optical instrument that allows light to enter a normally light-tight space. In film cameras, it exposes the photographic material beyond the intended image-forming light; in digital cameras, it can overload or contaminate the sensor exposure. Common causes include deteriorating foam seals around a film door, gaps between interchangeable camera parts, cracked bellows, pinholes, or leaks around mechanical controls. Light leaks were traditionally treated as faults to be repaired or temporarily blocked, but their status changed within experimental and vernacular practices, including Lomography and late twentieth-century avant-garde photography, where they could be valued as visible signs of chance, material instability, or resistance to polished photographic finish.

Visually, light leaks appear as red glare, diffused streaks, fog patches, veiling, or dull layers that sit over the depictive image. They may soften contrast, obscure detail, or introduce nondepictive marks that interrupt the illusion of a transparent photographic record. Their occurrence depends strongly on equipment and working conditions: pinhole cameras, aging bellows cameras, modular medium- and large-format systems, and improvised portable darkrooms are especially vulnerable when light-tightness is difficult to maintain. Photographers may also create the effect intentionally by exposing a camera body to light, exploiting end-of-roll accidents, reusing damaged negatives, or adding simulated light leak overlays in digital editing.

Experimental photographers often treat light leaks as part of a broader aesthetics of defect, grouping them with blur, grain, scratches, and other challenges to photographic control.