Abstract: A waste water cleaning system for use with apparatus for processing exposed lithographic plates, the processing apparatus receiving wash water for use in the processing. The cleaning system includes a centrifuge for removing contaminants from waste water from the processing apparatus, the centrifuge having an inlet for receiving waste water from the processing apparatus and an outlet for discharging the cleaned water. The cleaning system also includes means for carrying the waste water from the processing apparatus to the inlet. The cleaning system further includes control means for controlling the operation of the processing apparatus and the centrifuge. The control means includes means for starting the centrifuge and means for starting the flow of wash water into the processing apparatus a first predetermined time after the start of the centrifuge.

Abstract: A method of and apparatus for exposing boards which are photosensitive on both sides, for production of printed circuits on both sides, to light through films on both sides in which a lower film, a board, and an upper film in registered position on a light-transmitting platen are pressed down by a window and exposed to light on both sides through the platen and window, the window, gripping the upper film, is raised, the exposed board is removed, another board to be exposed is applied to the lower film on the platen, the window is lowered to apply the upper film to the new board, and the procedure repeated.

Abstract: An apparatus for exposing boards which are photosensitive on both sides, for production of printed circuits on both sides, to light through films on both sides in which a lower film, a board, and an upper film in registered position on a light-transmitting platen are pressed down by a window and exposed to light on both sides through the platen and window. A pair of registration pins are adjustably positioned in spaced relation along an edge of the platen and corresponding holes in the boards are used to align the boards and films for exposure. The pins are spaced as widely apart as possible to provide maximum registration between boards of varying sizes and films.