Deep Dive Into a 1960s Printing Plate Exposure Timer!

The VISOMAT BWS2 is an obscure '60s East German made device which measures the amount of light using a photocell and advances the wind-up mechanism with an adjustable stop. After the operating dial returns to its neutral position, the exposure lamp is switched off. It's built in a heavyweight die-cast aluminum enclosure (an order of magnitude more than enough to make @EEVblog drool!), industrial strength. Spare no expense, cost no object! And it's so simple - all electromechanical, not too much electronics in it. The only semiconductor here is a single-wave selenium rectifier. My unit comes from the Book Art Museum in Łódź, where I worked for five years. We had a small dark room in the very heart of the basement, that was used for exposing the photosensitive aluminum plates for offset printing. It had an enormous Klimsch UV light exposure device that was in a state of disrepair ever since, and it originally used arc discharge lamps as a source of light. At some point of the machine's