Toronto. We are spoiled today. Our digital cameras automatically adjust settings to match the light. What was coal black a century ago is like daylight today. When dry plates and roll films arrived on the scene, development was split from exposure. A plate or film would be processed hours or days after the exposure. This made it critical that the exposure was correct.
Many gadgets and tables were produced all with the objective to give the aspiring photographer an idea of what setting to use for a given scene. In addition to tables and calculators, extinction meters and even exposure meters were offered. Sadly the extinction and exposure meters were far too slow to be of use. Even when I was a youth in the late 1950s, exposure meters were so slow that flash was preferred indoors or outdoors late in the afternoon and in the night (unless special effects were desired).
Close ups and non-flash exposures in poor light required a sturdy tripod or holder and a carefully calculated estimate of exposure time. It was common at the time to use exposures both longer and shorter in time to bracket the estimated correct duration for important shots.
In 1923, Kaufmann of Puteaux, France introduced this complex calculator to determine the correct exposure outdoors and even indoors. The hand held calculator noted that “Autochromes would require 60 times [the exposure] for ord. rap. em (ordinary rapid emulsions)”.
I got my “Le posographe” from the late Bill Kantymir. Bill was happy to sell it to me because he had been able to find one in better condition – no small task at the time.
The late Brian Coe, in his wonderful book “Cameras from Daguerreotypes to Instant Pictures” published by Crown in 1978, devotes a chapter to Exposure Meters. All of the book’s illustrations are drawings – some in colour, others as plain line drawings. The exposure meter chapter also covers the elaborate calculators, tables, extinction meters and exposure meters. The chapter closes noting the demise of the hand held meters (Weston, Luna-Pro, etc.) as cameras began to be sold with decent built in exposure meters.