ACTINOGRAPH SLIDE RULE EXPOSURE METER CALCULATOR 1888

Description

Ferdinand Hurter (1844-98) and Vero Driffield (1848-1915) were granted British patent number 5545 on 14 April 1888 for a slide-rule exposure calculator. The device was sold as the Actinograph, initially by themselves and later by Marion & Company of London. It was the first calculator to be based on careful scientific observation, and thirteen different models for different latitudes were manufactured. Hurter and Driffield were the first to establish methods of sensitometric measurement that allowed the development of dry plates with a standardized measurement of their sensitivity, and the development of instruments to measure photographic exposure.

Guaranteed old and original.

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Shipping/postage and packing quotes shown below are non negotiable, please take them into account before you bid.

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Discount for combined purchases where weight and value permit.

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— Michael Pritchard

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Hurter & Driffield's Actinograph

Mahogany and printed paper slide rule photographic exposure calculator, printed date 1888.

In excellent condition and fully functioning, the catch on the box is part missing and the card outer box has a few light abrasions.

Width of mahogany box 4,1/2" or 115mm.,

total weight 215 grams.

With 4 booklets, 2+2 (2 spare)