slipping into history

remember the photographic slide-rules promoted in this ad?

Toronto. Post war, nomograms were great marketing tools. Arel, Inc. of St. Louis took it a step further creating an actual slide-rule, not with the traditional A, B, C, D, etc. scales but with calculation scales of interest to serious photographers.

I suspect only a smattering of keen amateurs even thought about the material offered by the ‘slide-rule’. Did you ever use (or even see) one? Most films came with a paper outlining exposure and processing information. For the curious, Morgan & Morgan’s Photo-Lab Index and the series of Focal Press books did the rest.

In time, cameras, lens, and film sensitivity improved to the point that flash bulbs and the needed calculations were unnecessary (simple charts abounded any way). Electronic flash came along simplifying exposure (professionals still chose to adjust speed and exposure manually, over-riding any automation). Hand held exposure meters gave exposure data. Later built-in meters eliminated any need at all for the average snap-shooter to make exposure adjustments.

Late last century on, the digital era took over and with the cameras’ “auto everything”, most people neither knew nor cared about the now quaint concepts that the ‘slide-rule’ demonstrated.

Thanks once again to my good friend, George Dunbar, for sharing this snippet of history (from the December, 1946 issue of Popular Photography) with us! Note: I repeated the link here for the viewer’s convenience.

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