In 1902, a German physicist named Arthur Korn filed a patent for what he called the Bildtelegraph — a machine that could transmit photographs over ordinary telegraph wires. By 1907, he had refined the system enough to send a photograph of the Crown Prince of Germany from Munich to Berlin to Paris to London, a distance of over 1,800 kilometers. The image arrived in roughly twelve minutes. Newspapers across Europe printed it the next morning. The patent — filed in Germany and later in the US as US Patent 1,030,427 ("Apparatus for the Electric Transmission of Pictures") — quietly invented the entire field of facsimile communication.

The mechanism was beautifully clever. Korn wrapped a photographic transparency around a rotating glass cylinder. A point source of light shone through the spinning image onto a selenium photocell — selenium's resistance varies with light intensity, a property discovered in 1873. As the cylinder rotated and slowly translated along its axis, the photocell read out the image as a continuous helical scan, converting brightness into a varying electrical current. At the receiving end, that current modulated a light source aimed at a second rotating cylinder wrapped in photographic paper, synchronized via tuning forks. Bright pixels became bright spots; dark pixels became dark spots. The image rebuilt itself line by line, thousands of kilometers away.

Every element of modern raster image transmission is already present:

• Raster scanning — the helical sweep is functionally identical to how a CCD sensor reads pixels row by row, or how an inkjet printer lays down lines.
• Photoelectric digitization — selenium was a primitive but real analog-to-electrical converter, the great-grandparent of every CMOS sensor in every phone camera.
• Synchronized sampling — Korn's tuning-fork synchronization is the same problem solved today by pixel clocks and frame-sync signals in HDMI.
• Long-distance image transmission over existing infrastructure — sending pictures over telegraph wires is the conceptual seed of sending JPEGs over copper telephone lines (dial-up modems) and, ultimately, fiber.

The commercial impact was immediate and enormous. By 1910, Korn's system was being used by European newspapers to share wire photos. The technology was licensed to the French police, who used it to transmit mugshots between cities — the first photographic identity database operating at electrical speed. AT&T's Bell Labs adapted the same principles for the 1924 transatlantic photo service, and the Associated Press launched its famous Wirephoto network in 1935 using direct descendants of Korn's scheme.

Fast-forward: the office fax machine boom of the 1980s, which seemed like a sudden new technology, was Korn's invention with the selenium swapped for a CCD and the tuning fork swapped for a quartz crystal. The medical world quietly kept using it — modern teleradiology (sending X-rays between hospitals) descends directly from the same scanning logic. Even the line-by-line progressive rendering you still occasionally see on slow JPEGs in a browser is, conceptually, Korn's helical scan playing back in real time.

What makes Korn's patent astonishing is the date. In 1902, the Wright Brothers had not yet flown. Einstein had not yet published special relativity. Radio was a novelty. And a Bavarian physics professor had already built a working pipeline for transmitting digital-style raster images over a continent-spanning network — a century before anyone would think to call it "image messaging."