Time

This is the second article in an occasional series, which takes a look at the origins of basic photographic theory. The last article dealt with the topic of aperture. This one concerns exposure time, commonly known as ‘shutter speed’ – for reasons that will be discussed later.

As before, use will be made of historical research papers, which provide a first-hand account offrom August 1858 to September 1860. The term ‘shutter’ does not appear in any of the articles, and those that do mention the ‘time of exposure’ generally identify a suitable time as being several minutes on a bright day. A watch and a lens cap was amply sufficient to control it.