Electrophotography

The Xerox flat plate system (electrophotography) is relatively unknown in the history of photography. One of the reasons for this is that it was never intended to be used as a creative tool for artist and photographers. It was developed to make copies of typed office documents. Another reason for its obscurity is that it was used predominantly in the Rochester area by artists who were able to acquire this equipment. Xerox Corporation is based in Rochester NY. Often work produced with the flat plate system is categorized as “copy art” because it was produced with a xerographic process. Unlike other copy art the flat plate system is a completely manual camera based process requiring multiple steps and knowledge of photography. The process that a modern photocopier goes through in a few seconds is a manual step in the flat plate system. Charging, exposing, developing, transferring and finally fusing all must be carried out by the user. Because the process is broken down into separate steps there are many opportunities for adjustments and manipulation.

 

Xerox Camera
Selenium Plate

The selenium plate is placed in the charging unit. The plate is exposed to thousands of volts of electricity giving the plate a positive electrostatic charge .

A dark slide is slid into the plate holder to protect it from light.

The #4 camera is focused on its subject as one would with a traditional medium or large format camera.

The ground glass is removed and selenium plate is inserted. The Dark slide is pulled out and the exposure lasting anywhere from a few seconds to a few minutes is made. The areas of the plate that are hit with light lose their positive charge.

The plate is now ready for development. The plate is placed on a tray full of toner and carrier beads. The toner is negatively charged. The dark slide is removed and the plate is rocked back and forth. This is known as cascade development. The toner is held to the carrier beads with an electrostatic charge. The parts of the plate that have not been exposed to light still have a positive charge stronger than the carrier beads thus pulling the toner off or them and adhering the toner to the plate.

When the plate is removed the image is complete and should be visible as a revered positive. Like one would see on a Daguerreotype.

At this point the image can be transferred. A sheet of paper is placed over the image taking care not to move the paper causing the image to smudge.

The plate and paper are placed back into the charging unit and the same electrostatic charge used for charging the plate is used to “lift” the negatively charged toner onto the piece of paper. The plate is pulled out and the paper is lifted off.

The image is now no longer reversed and is ready for fusing. At this stage before fusing one can smudge, draw on or transfer the image to other surfaces. 

Xerox 1218

The Largest flat plate system built. As far as I know none still exist

 

 

 

© 2015 Tom Carpenter