Tales of Experimental Photography
Light plane photography (LPP) is a photographic technique that uses a plane of light and a camera to record photographs with unique optical effects.
A light plane is a thin plane of focused light from a specialized light source. Unlike light from a conventional, unfocused source, light from a suitable source for light planes does not spread to a three-dimensional sphere or a cone but is focused to a two-dimensional plane. In most cases, the light plane is the only light source in LPP and any ambient or stray light is avoided.
In a typical setup, a camera is placed perpendicularly to a light plane, facing the light plane. The installation is inside a dark environment. Camera and light plane have fixed positions, long exposure times are used. As long as nothing is crossing the light path the recorded image remains black. As an object moves into the light, its contours are gradually illuminated. Over time, an image is recorded by adding the contours to a comprehensible projection of the object. Different regions of the image are recorded at different times.
In contrast to traditional photography where subject movement is avoided in most cases, the movement and its choreography are central to LPP. When LPP images of people are recorded, it’s typically the model who is creating the image by moving through the light plane using a choreography.
From the point of view of the camera, the light plane reduces our three-dimensional space to two dimensions. There is no depth, anything in front and behind the light plane is invisible to the camera. Any object crossing the plane has, at any given moment, only a two-dimensional contour.
In the resulting image, one spatial dimension (depth) is exchanged with time (movement). Different regions correspond to different points in time. But unlike slit scanning, another photographic technique that adds time to the recording process, there is no fixed direction of the time dimension in a LPP image.
It’s the movement (time) which is creating comprehensible images. Without movement all we would see is the 2 dimensional contours of the subject.
A light plane photograph can be thought of as a parallel projection of a 3 dimensional space-time (two spatial and one time dimension).
Laser diodes with line generating optics (line lasers) are the most common light sources in LPP. Line lasers create a very thin and almost perfectly parallel light plane. They are small and multiple line lasers can be calibrated into one combined light plane.
When using conventional line lasers modules to create the light plane, the resulting photographs are monochromatic. To introduce more colors it is possible to use multiple planes with different wavelength lasers. In order to create near-real-color images, more advanced laser modules with 3 laser diodes (red, green and blue) can be used. The three colors are optically combined into one single RGB light plane.
An example video of what it looks like when a model moves through a light plane:
Light plane photography is similar to scanning sight photography described by Charles Kazilek and William Sharp and was inspired by it. Scanning light photography was used in the film era to increase depth of field in macro photography.
To the authors knowledge, this is the first article describing light plane photography.
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