Phototelegraphy: inventions that transported images worldwide

Museum for Communication Berlin, Museum Foundation Post and Telecommunication

Today, smartphones are used to send pictures. Before the digital age, this required sophisticated technology called phototelegraphy. Inventors have been working to improve this since the first electronic picture transmission in 1847, making international picture broadcasts possible as early as the 1920s.

Electric pictures
To start, how do you solve the technical challenge of converting images into electrical impulses and putting them back together on the receiver's side? Since 1843, inventors have been experimenting with electric inks and scanner devices. At the end of the 19th century, they developed the first devices that could transmit manuscripts and drawings, starting the success story of phototelegraphy.   

Copy telegraphs transfer writing movements into currents and "copy" them in the receiver using a mechanical writing mechanism. Manuscripts and drawings could therefore be sent directly over the telephone wire, up to 300 miles away.

Gustav Grzanna developed a new method for reproducing the currents received. His telautograph converted them into "light writing" and reproduced the telautogram photographically.

Each point on the writing surface corresponds to a different current strength. The stylus position is then transmitted to the receiver as successive impulses.

The receiver when closed creates a dark space. Two small mirrors, moved by the transmitted impulses, direct a beam of light over photo paper and record the message as "light writing."

An electric motor then transports the light-written message to the side output slot while sealing it with developer liquid—all fully automatically.

Arthur Korn, on the other hand, used a synchronized process for recording and reproducing picture information. He used 2 rotating cylinders: one in the transmitter, and another in the receiver.

The message is written in ink on zinc foil before sending. As a result, the surface is composed of electrically conductive and non-conductive points.

In the transmitter, the original is wrapped around a rotary cylinder and scanned by metal pins in a spiral as a line grid. When they encounter the points described, the current flow is interrupted.

In the receiver, a negative is exposed with this information on a cylinder running in sync. The line grid is then put together as a photographic copy of the sent original.

In 1904, Arthur Korn successfully sent the world's first electrical transmission of a photograph, using his specially developed "photoelectric process." The 2 rotating cylinders and photographic recording of the "telautograph" have been preserved, but the transmitter now only illuminates a transparent image film. Korn's phototelegraph registered the changing brightness levels of the transmitted light as current values using the semimetal selenium. The voltages of these values corresponded to the tonal values of the photograph, exposing a negative in the receiver. However, selenium reacts slowly to light, resulting in long transmission times and mediocre results.
August Karolus developed a highly sensitive photocell in 1923. With better transmission quality and shorter transmission times, he made phototelegraphy marketable. The Karolus-Telefunken system led to the establishment of the first permanent phototelegraph line in Germany in 1927. 

Thanks to modern photocells, photographs could be wrapped directly around the transmitter cylinder. The direct illumination provided enough light reflection to transmit quality pictures.

With "photoelectric" scanning, Arthur Korn and August Karolus introduced a method that came to be used worldwide. It defined phototelegraphy up to the 1980s.

Early multimedia
In the late 1920s, image broadcasting was set to take us into the future. Radio stations and services broadcast image signals via radio waves, which were received at home by special image radio receivers. Directly connected to radio devices and combined with a commutator, they were some of the first multimedia systems. But this was short lived; a few years later, image broadcasting was discontinued due to poor sales.    

The fultograph brought broadcast images directly into the living room. It reproduced the image signals on special paper using photochemicals.

Image broadcasting was revolutionary for weather reporting. You could now send the latest weather maps with plotted and marked meteorological data.

Public imaging stations
In the 1930s, the German Reichspost expanded the phototelegram service with public imaging stations. These were the "travel agents" of photos and helped phototelegraphy become popular. After being interrupted by the Second World War, the imaging stations started running again from 1950. Due to increasing competition from new image media—namely, the telefax service—the phototelegram service was suspended across Germany in 1984.

Together with the Reichspost, Siemens & Halske developed 2 new imaging devices from 1936. The fixed image receiver became a standard in public imaging offices.

Portable transmission cases made phototelegraphy mobile. Temporary imaging stations now added to the phototelegram service.

Public and mobile imaging stations increased interest in phototelegraphy. From 1934 to 1939, the number of phototelegrams sent yearly increased from 200 to 40,000.

Alongside press agencies, newspapers, and businesses, more private customers were also using the phototelegram service to send personal picture greetings to loved ones far away.

Rudolf Hell KG established itself as the leading manufacturer of imaging devices in Germany in the post-war period. In 1951, the company developed cabinet F-type devices specifically for the Bundespost.

The C-series compact devices followed in the mid-1950s. With 12 different models, Rudolf Hell responded to the leap in the market for imaging devices.

In the early 1960s, Bundespost post offices were fully equipped with Hell's imaging devices.

The CAFtrans 993 was commonly used, including for the growing international photo traffic which used a range of standards.

In addition, test images increased the quality of image transmissions worldwide.

Pictures for the global village
Phototelegraphy changed journalism for good; daily news from around the world could reach press agencies in minutes via wired and wireless connections.

Portable transmitters such as the DPA were particularly essential for press agencies. They sent photos around the world in less than 12 minutes via shortwave frequencies.

From 1984, digital photo transmission took journalism into a new media age. First, image transfer devices such as Hasselblad's Dixel 2000 replaced phototelegraphy. From 1991, these were replaced by digital cameras and laptops.

From facsimile to fax
New technologies replaced phototelegraphy in business and private sectors as well, with the Siemens-Hell KF 108 fax machine being the first. It recorded transmissions directly onto plain paper, meaning pictures and text documents could be exchanged quickly. The term "fax" stems from the concept of the electric facsimile, which was already being pursued by the pioneers of phototelegraphy in the 19th century.       

On January 1, 1979, the telefax service was launched in Germany. With automatic feeders and easy-to-use keypads, fax machines weren't just for the office—they quickly became a part of everyday life.

Phototelegraphy was finally replaced completely by digital fax machines with message storage and mass mail functionality. On December 1, 1984, the phototelegram service was suspended across Germany.

Credits: Story

Phototelegraphy: inventions that transported images worldwide

A virtual exhibition by Museumsstiftung Post und Telekommunikation.

Curator: Joel Fischer

All objects are part of the collection of Museumsstiftung Post und Telekommunikation.

Rolf Barnekow u. Manfred Bernhardt: Die Vorläufer der Telefaxgeräte, in: Post- und Telekommunikationsgeschichte, Heft 1, 1995, S. 57–62.

Joel Fischer: Das "Zauberkabinett der Technik". Gustav Grzannas Kopiertelegraf "Fernschreiber System Lichtschrift", in: Das Archiv. Magazin für Kommunikationsgeschichte, Heft 1, 2018, S. 76-79.

Bernd Flessner: Bilder aus der Ferne. Die Entwicklung der Bildtelegrafie, in: Das Archiv. Magazin für Kommunikationsgeschichte, Heft 1, 2012, S. 28–33.

Roland Gööck: Die großen Erfindungen. Nachrichtentechnik, Elektronik, Künzelsau 1988.

Bildtelegraphie. Eine Mediengeschichte in Patenten (1840–1930), hrsg. v. Albert Kümmel-Schnur u. Christian Kassung, Bielefeld 2012.

Franz Pichler: Elektrische Bilder aus der Ferne. Technische Entwicklung von Bildtelegraphie und Fernsehen bis zum Jahre 1939.

Handbuch der Bildtelegraphie und des Fernsehens, hrsg. v. Fritz Schröter, Berlin 1932.

Credits: All media
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