Wirephoto
1 January 1935 (AP Wirephoto)
Photographs sent over telephone lines as varying electrical signals, scanned at one end and redrawn at the other, so news pictures reached papers across a country the same day.
How it began
Arthur Korn sent photographs over telegraph wires in Germany in 1907, and AT&T offered a service in the 1920s. On 1 January 1935 the Associated Press opened a network linking newspapers across the United States.
How it works
The print is wrapped around a rotating drum and scanned line by line by a light and a photocell. Brightness becomes a varying electric signal sent down a phone line. At the other end a light, varied by the signal, exposes photographic paper on a drum turning in step.
Why it mattered
The first picture sent on the AP network showed a plane crash in the Adirondacks. Newspapers could print pictures of distant events the same day, and agencies built their business on it.
Limits and what replaced it
Quality was modest and each picture took minutes. Digital cameras such as the Kodak DCS and the internet replaced it.
Today
Replaced by digital transmission; news photos now travel instantly over the internet.