Slot-scan or strip-scan, strip-camera work is a richly populated strand of alternative representation in photography. A single strip or row of pixels from the image is joined with successive similar strips to present a linear history of that slice over time.
It is crucial to note that only parts of the scene that fall in the plane of the slot projected forward from the camera can figure in the finished image and only where a object passes through that plane can the object be depicted in its entirety. Object that do not move in the plane of the slot are registered as continuous bands of shade. As an object passes through the plane more or less slowly it will occupy more or less space in the image. Thus with reference to Jay Mark Johnson's image "EL ANARQUISTA Y EL AUTOMOVIL" the cars are foreshortened relative to the pedestrian, the tips of the pedestrian's feet are narrowed by their greater velocity relative to the pedestrian. Objects that move quickly through the plane are recorded in fewer strips and appear shortened.
A great deal of the work in this field is made in post-production manipulation of continuous video footage, this enables working with a strip of a single pixel width and resolution equivalent to the original footage, and see below . I choose however to work in film and my strip camera is built from a 1966 manual "M12" Hasselblad magazine, fitted with a slotted darkslide and driven with an electric screwdriver. By timing the run through of a 120 film spool, about 12 to 15 seconds and guessing the slot width, 0.005 inches, I estimate an effective shutter speed of 1/200 second and set an aperture accordingly. Any irregularity in film advance speed upsets this calculation and barring appears in the finished image.
My more recent work is to walk through the scene holding the camera in front of my body to probe the space using the projected film plane. When the camera is rigidly fixed the recorded image only registers moving objects and reflects the continuous (read, smooth) nature of their motion. When I move carrying the camera stationery, inanimate objects are recorded and the images of moving objects are interpreted by the relative difference in our motion. The pace of my movement is noted in the vertical displacement of the finished image, it is likely also that small side to side motions while I walk leads to double recording of objects.
My intention in this mode of working is to define a serial intervention in space and time and to summarise the passage of the performance in the image. For example while I walk though a car park and note a funfare my shadow is captured and the act of my motion and turning is recorded. The performance here has parallels with Fiona Harvey's work Movement through Space, 2010 where in some sense the performer carries a [photographic] "canvas" through the performance space, catching the incident light using a long exposure. In this strip camera work, the "canvas" being carried through the space is at a right angle to Harvey's. The choice of orientation of this plane is part of the performance, I may point it to capture or avoid objects; where these are autonomous, perhaps people walking in front of me, the extent to which they register in the image is an accident of my motion relative to the object. Like Harvey, like Jackson Pollock there remains an unpredictable and non repeatable quality to the finished image.
Short film (5.1Mb, 1'30") digitally processed, real time slit scan
programming by Aldobranti