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How It Works

It took a few minutes to work this thing out. As evidenced by a pair of pivoting arms and guides inside the cabinet, there is either a piece missing, or some sort of accessory could be added. My guess is there should be an additional piece of frosted glass to help reduce the quantity of light escaping through the timer display. A back (also missing) slides into a groove cut in the sides and base. With the lamp located where it is, one must assume this would be a fabricated tin panel which enclosed the bulb. However, I won't swear the bulb holder is original to the device. If the light source were not enclosed, it would have to be continualy switched on and off.

Open the front

Pull down spring loaded latches on either side of the cabinet and the front panel opens. (The thin protrusion on the upper right is the latch handle. the left side is the same but the handle is missing.)

Place Negative in the Center

The knob on the left turns counterclockwise against a spring. Two small arms at the top alternately grip the negative against the windows, or push the negative out so it can be grabbed and removed when the knob is turned.

Place Unexposed Slide on Left

Now close the door and expose the plate. The timer will be explained later. A spring loaded lever in the door holds the plate firmly against the negative. Once exposed, open the door.

Shift Half Exposed Plate to the Right

The knob on the right pulls out. An arm with a tab which goes under the edge of the plate draws the plate to the right. A guide at the top of the arm tilts the plate forward so it will clear the negative retaining arm, which then acts as an edge guide. Now close the door and expose again.

Back View and Clock Operation

What makes the Automatic Inverseur more clever than a standard print frame is the clock and its method of operation. A wind up clock, located on the base, is started by pulling out the lever on the right. This is left running while the device is being used.

Turning the lever on the left counter clockwise does two things simultaneously. A red lens, hinged at the bottom, flips down allowing white light to expose the slide. At the same time, the timer needle on the front is engaged and starts counting up. When the knob is turned back, the window filter closes and the timer needle resets to zero. It was thus possible to achieve accurate and repeatable exposure times.