Slit Scan Stretched Time Photo

Slit-Scan - Stretched Time Photography

Slit-scan photography captures time across a single spatial dimension, producing images where the horizontal axis represents space and the vertical axis (or the other way) represents time. A narrow slit aperture scans across the scene, building the image strip by strip - subjects that move during the scan appear stretched, compressed, or multiplied; stationary elements appear normal. The result reveals temporal events invisible to the normal frame.

The Starggate: Douglas Trumbull and 2001

The most culturally significant slit-scan moment is the Stargate sequence in Stanley Kubrick's 2001: A Space Odyssey (1968). Effects supervisor Douglas Trumbull developed the specific technique by mounting a camera on a rail and moving it toward a slit backlit by colored artwork on a rostrum frame, with long exposures capturing the approaching slit as a smeared, streaking tunnel of light. The technique took nearly a year to perfect and approximately seven months to shoot. Trumbull later patented variations and used them in Close Encounters of the Third Kind (1977), Star Trek: The Motion Picture (1979), and Blade Runner (1982).

Marathon Photography and Sports Finish-Line Imaging

Slit-scan has a completely separate practical application in race finish-line photography, used continuously since the 1940s. A camera positioned at the finish line with a vertical slit aperture records a continuous horizontal strip as athletes cross - the image shows every competitor at the instant they crossed the exact finish line, with their bodies stretching or compressing based on their speed relative to the scan rate. This produces the authoritative finish photograph used in Olympic events, horse racing, and cycling.

Joon Yong Park's Train series (2009) applied the race finish-line principle to street photography, scanning moving trains and pedestrians to produce dreamlike ribbon-images where bodies become fluid streaks and architecture holds still. Andy Davies' ScanCamera app (2001-era concept, widely implemented on iPhone from ~2009) made slit-scan available to anyone with a mobile phone.

The Temporal Ribbon

Contemporary slit-scan applications include panoramic photography scanners repurposed for temporal capture (Noblex rotating cameras), custom Processing/openFrameworks implementations, and commercial After Effects plugins. Ryoji Ikeda's data.matrix and test pattern works use mathematically derived slit-scan principles at monumental scale. Instagram and TikTok effects including the "time slice" filter popularized the look to billions of users.