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Fresh Pictures for the Newspaper Offices

By A. Morell Nielsen

Already in 1929, the picture telegraph was introduced in Denmark. The editorial offices were pleased with the novelty and used it until eventually they acquired their own telephoto equipment. The picture telegraph was also the predecessor of the later successful fax machine.


Most people know a fax machine. It is considered by many to be an innovation, but this is only true to a certain degree because transmission of pictures by means of electric impulses has existed for a long time.

In Denmark the invention of the "picture telegraph" was followed with interest as it offered the opportunity of providing the editorial offices with fresh foreign illustrations when, hitherto, they had had to wait for the mail to arrive and by then a press photo might already have lost its news value.

On 1st March 1929, the picture telegraph connection Copenhagen-Berlin was opened as the first of its kind in Denmark. The equipment had been designed by the German physicist Karolus and in broad outline his transmission system can be described as follows:

Complicated Process

A strongly luminous glow lamp transmits a beam of light through a lens system generating a very strong luminous spot of about 1.25 mm2 on the image which is to be transmitted. The image is fixed on a rotating cylinder and the luminous spot is transposed in the longitudinal direction of the cylinder, by which the entire picture is gradually exposed in a helical line.

The light is thrown back with varying intensity depending whether the spot passes across bright or dark parts of the image. This is being picked up by the light-sensitive coating of a photo cell, and in that way electrons are disengaged which wander to the anode, and current proportional to the intensity of light is taken from a battery.

In order to transmit the current variations to the receiver they have to be "overlaid" a carrier frequency. This is generated by placing a serrated wheel in front of the glow lamp, which interrupts the beams of light about 1,300 times per second.

A Monstrosity

A transmitter like the one described above is on display in the museum and it is by no means a handy device like a fax machine, but rather a monstrosity weighing about 250 kilos. In the receiver, which is not on display, the changing current is transformed into a changing quantity of light which is concentrated in a small spot which is wandering across a film membrane in the same way as the transmitter.

The maximum size of the picture was originally 18 x 26 cm and the finest sharpness of image 5 lines per mm. Under these circumstances it took 19 minutes before the entire film was exposed. Thereafter the negative was developed and the picture copied.

Cheaper than Telegrams

To evaluate whether this was an expensive way of transmission, we can, of course, only compare with text telegrams. The minimum charge for a picture telegram was DKK 10 and as an ordinary telegram to Berlin cost DKK 0.16 per word, it became cheaper to send a type-written text of more than 62 words as a picture telegram.

The picture telegraph could not hold the fort in the long run because of the limitation that the telegrams had to be sent between certain telegraph stations and transported to and from these in the old-fashioned way by messenger. Consequently, only the newspapers and picture bureaus in the capital were able to actually benefit from the system. Although it was soon extended with a direct connection to Stockholm later during 1929, to London the following year etc., the distance between stations and customers remained too far.

The Tele Printer Came

Moreover, decisive improvements were made in competing fields. A nightly airmail service was introduced in 1930 which reduced the time of transmission of letter post between Denmark and foreign countries considerably and during the 1930’s the tele printers made their entry which rendered pure text telegrams per picture redundant.

Last, but not least, the editorial offices and other major users eventually got their own telephoto equipment. The Siemens-Karolus equipment held the fort until 1956 when it was replaced by the more modern Hell picture telegraph, which was, however, not much used either. It was taken out of service in 1973 and can also be seen in the museum.

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