What is pinhole photography? A how-to guide

Pinhole photography reduces a camera to its essentials: a light-tight box, a tiny opening and a surface capable of recording light. There is no lens. Light reflected from a scene passes through the hole and projects an inverted image onto the opposite wall. Because the opening is so small, much of the scene appears relatively sharp—but very little light enters. Exposures stretch from seconds into minutes, hours or even months, turning movement into blur, ghosts or empty space. It is the ancient camera obscura principle made permanent.

To build one, begin with a rigid cardboard box or tin with a tight lid. Paint or line the interior matte black, then tape every seam so the pinhole is the only entrance for light. Cut a small square opening in one side. Tape a thin sheet of tin or aluminum over it, smooth its edges, and gently press a fine sewing needle through the center. A clean, round opening produces a cleaner image.

Cover the hole with a flap of opaque black tape. This is the shutter. In darkness, attach the recording surface to the inside wall opposite the hole, with its sensitive side facing the pinhole. Close and reseal the box. Place it on a stable surface, aim toward a bright, motionless scene, lift the shutter and begin the exposure. Make several tests, doubling the exposure each time.

The recording surface determines what happens next:

• Sheet film produces a conventional negative. Black-and-white or color film can be developed, printed and scanned using the same processes as other large-format film.

• Ordinary black-and-white photographic paper produces a paper negative. Develop, stop, fix and wash it, then scan it and digitally invert its tones—or contact-print it onto another sheet. ILFORD suggests treating its Multigrade papers as roughly ISO 3–6 when beginning exposure tests.

• Color enlarging paper can also make a color paper negative. It must be loaded in complete darkness and processed in RA-4 chemistry. After scanning, invert both its tones and colors, then correct the resulting cast.

• Specialty direct-positive paper creates a finished black-and-white positive after normal paper processing. The result is slow, high-contrast and mirror-reversed, but requires no negative. The physical sheet can simply be scanned.

At the experimental edge, commercial photographic material can be replaced with plant pigment. Mash blueberries, spinach, beetroot or another strongly colored plant, strain the liquid, brush thin coats onto absorbent paper and let it dry in darkness. Light slowly destroys—or bleaches—the exposed pigment, leaving stronger color where less light arrived. This is an anthotype: a bleached-in image rather than a chemically developed one.

Natural dyes are dramatically less sensitive than film. One documented in-camera anthotype experiment required months even with a fast lens; a pinhole would likely be slower. A controlled, high-output UV-rich source may accelerate testing, but a pinhole cannot itself amplify light. Use a cool exposure source with appropriate UV protection, and never concentrate sunlight or leave a hot lamp against cardboard.

Anthotypes also cannot be fixed permanently. The image will continue to fade, making its scan part of the finished work.

The appeal of pinhole photography is not technical perfection. A box, a pinprick and time are enough to let light construct an image.