Name of tool: Image Processor
Alternate name: Sandin Image Processor, I.P., Analog Image Processor
Inventor/Designer: Daniel J. Sandin
Date of design: 1973
In the late sixties, Daniel Sandin studied the plans for the Moog Analog Synthesizer
, developed in 1964 by Robert Moog, and was inspired to design the structure of a tool for processing video signals. He then attempted to adapt the different modules of the Moog
to a system suited for video data and display of resulting images on an NTSC monitor. Sandin also hoped to design a video tool that artists well-versed in electronics could build themselves inexpensively. He eventually met Philip Morton, a man who played a key role at every design stage of the Image Processor.
Morton drew up the plans and helped Sandin to solve several technical problems before the prototype was built. Thanks to a grant from Kent State University (Kent, U.S.), Sandin completed the first version of the Image Processor
around 1972. This version was presented to the public in a performance titled “Inconsecration of New Space: A Color Video Collaborative Process” at the University of Illinois (Chicago, U.S.) on January 26, 1973. In the mid-seventies, a colour encoder (see Operating Mode) was added to the black and white signal processing modules. During the same period, Sandin distributed a manifesto titled “Distribution Religion,” which encouraged artists to obtain free plans of the Image Processor
so they could build their own copy (and even modify its components). He set out a single condition for this exchange: artists had to convey the results of these modifications in any way they wished (photographs of the altered modules, videotapes made with this device, and other manifestations of its use). The Experimental Television Center at the State University of New York (Binghampton, U.S.) still possesses a functional copy to this day.
Description of the tool
The Image Processor
consists of a series of boxes that contain modules. As the original plans for the device are often freely interpreted by those who build a copy (see Historical Notice), the number and configuration of the modules may vary.
Brief list of materials
Modules of electronic components on processing rack.
List of components
General input module or camera processor/sync stripper; mixing and keying module or adder/multiplier; comparator; amplitude classifier; differentiator; function generator; reference module; oscillator; RGB colour encoder; NTSC colour sync generator; power supply; cables.
The Image Processor
is an analog computer designed to control the black and white signal generating the video frame. The Image Processor
fixes the voltage level of the signal by way of functions programmed in its modules. Each of the modules includes panels where cables are plugged to route the signal from one point to the other in the module and between the modules. When the signal passes between different modules, the functions combine and create a range of often random effects, which enhance the programmed effects. In addition to these many processing modules, the Image Processor
features an encoding component translating the luminance scale into coded values for the colour image. The general input module or camera processor/sync stripper is a set of components that represent the first entry point to the processing modules of the Image Processor.
The mixing and keying module or adder/multiplier allows for the juxtaposition, inversion, mixing and keying of two video sources (for example, the image from a camera or a tape recorder). The adder can shift the polarity of the sources. The multiplier juxtaposes the sources linearly: one control knob lets you shift directly from one signal to the next, another knob provides a mixing effect, and a third knob generates a cross-fade. The comparator is a high gain amplifier that replaces one video source with another and generates a clear cut between areas of the image while keying. The amplitude classifier consists of a series of voltage level comparators measuring the inputted signal in a scale of dark and light values. The outputted signal is displayed as eight areas delineated in the image, which correspond to eight levels of luminance (from black to white) controlled by knobs assigned to each delineated plane. The differentiator gives a unique luminance value to the ground and the figure, delineating the edges of these shapes. The function generator produces effects similar to photographic solarization, shifting from the positive to the negative and displaying three scales of luminance (white, grey, black) controlled separately by knobs. The reference module consists of nine potentiometers with input areas that route the electrical current to enable certain modules. The oscillator or waveform generator creates a sine and triangular waveform whose time of interplay on the video signal is dependent on the horizontal or vertical synchronization. Built from the colour encoder of a Sony camera, the RGB colour encoder translates the scale of luminance in RGB areas in the image. The dark values are coded in three colours (red, green, blue) and the brighter values are then displayed in complementary colours (it is possible to reverse the polarity and hence produce the opposite effect). The NTSC colour sync generator gives the appropriate shape to the image (horizontal and vertical synchronization signals, etc.). Finally, the Image Processor
is hooked up to a power supply equipped with a bus (a component dispatching various operations in the same circuit), which routes the electrical current to the different modules.
Controlling the black and white signal generating the video frame; keying; colouring the black and white signal.
Vasulka, Woody. — [Interview with Dan Sandin]. — 28 p. — Manuscript. — Transcription.
The Dan Sandin Image Processor. — [s.d.]. —  p. — Technical description. — Included in the file entitled "Morton, Phil".
Sandin, Daniel J. — Distribution religion. — [s.d.]. —  p. — Note. — Included in the file entitled "Morton, Phil".
[Morton], Phil. — Notes on the aesthetics of copying an image processor. — [s.d.]. —  p. — Notes. — Included in the file entitled "Morton, Phil".
[Image Processor (IP) : integrated circuits]. — [s.d.]. —  p. — Diagrams. — Included in the file entitled "Morton, Phil".
Vasulka, Woody ; Vasulka, Steina. — Eigenwelt der Apparatewelt : Pioniere der Elektronischen Kunst = Pioneers of electronic art. — Artistic direction by Peter Weibel, edited by David Dunn. — Santa Fe : The Vasulkas ; Linz : Ars Electronica Center, 1992. — 240 p. Also available on the Internet : http://www.vasulka.org/Kitchen/PDF_Eigenwelt/Eigenwelt.htm [ref. September 23, 2003].