Hurter and Driffield Actinograph. Small mahogany box containing exposure calculator
Hurter and Driffield Actinograph. Small mahogany box containing exposure calculator, slide rule type. Scales for plate speed: 0.5-300 H&D. Exposure time: 0.05-60secs. Aperture: f/2.8-65 52 degrees 30' 0".
More
An actinograph is a calculator used for estimating photographic exposure. Inside the box, the cylinder displays average daylight hours across the months of the year. The estimated available light on a given day could then be plotted against different intensities of ‘dull’ ‘bright’ and ‘mean’.
The actinograph could then be used to estimate the ideal aperture setting for the camera, and the optimum ‘speed’ of the plate.
- Materials:
- brass (copper, zinc alloy) and mahogany (wood)
- Object Number:
- 1990-5036/2624/1
- type:
- actinograph
