Wireless Transmission of Photographs: Second Edition, Revised and Enlarged 1919

In Short

This manual outlines the emerging technology of radio-photography, explaining how to transmit visual images through the ether without connecting wires. Marcus J. Martin details the fundamental mechanics, chemical preparation, and electrical circuits necessary to convert photographs into printable radio signals. He surveys early historical attempts by other pioneers before presenting his own invention, the "telephograph." The book endures as a vivid historical window into early communications technology, capturing the precise moment when photojournalism, optics, and wireless telegraphy combined to forge modern visual media.

The Story

The book opens by laying out the steep multidisciplinary requirements expected of any experimenter attempting radio-photography. Marcus J. Martin explains that transmitting image data over the air demands a practical grasp of chemistry, mechanics, optics, and electricity. He establishes the commercial necessity driving the field: the public's growing appetite for illustrated newspapers. Early wired experiments dating back to 1847 laid the groundwork, but recent breakthroughs in wireless apparatus promise cheaper and faster long-distance picture delivery. Martin details early trials, such as Hans Knudsen’s 1908 system utilizing smoked glass plates, while pointing out their severe mechanical limitations and lack of fine detail.

From these historical foundations, the narrative moves directly into the technical mechanics of image transmission. Martin walks through the process of taking a photograph, passing it through a line screen to break the picture into parallel bands, and transferring that image onto a flexible metal foil sheet coated with insolubilized glue. When wrapped around a revolving transmitter drum, a metal stylus moves across the surface. The stylus completes or breaks electrical circuits as it touches alternating bands of conducting metal and insulating glue, keying a wireless transmitter to emit wave pulses.

The second half of the book addresses the receiving end and the monumental challenge of synchronization. A receiver must capture these delicate radio pulses and translate them back into a visual image without losing detail or speed. Martin describes several experimental methods, including selenium cells, string galvanometers, and photographic films wrapped around revolving receiving cylinders. He then introduces his own proprietary system: the telephograph. This design utilizes a sensitive telephone relay attached to a tiny mirror, which moves a magnified light beam across an aperture in front of a photographic film, recording high-speed signals with minimal mechanical inertia.

Finally, the text concludes with exhaustive technical guidance and mathematical appendices. Martin offers step-by-step photographic recipes for amateur builders to construct their own lined metal prints, details exposure speed calculations, and analyzes the optical properties of lenses required to correct spherical aberration.

How It Unfolds

The baseline requirements Martin introduces the fledgling field of radio-photography, describing its dependence on four combined sciences and emphasizing the growing commercial demand for rapid photojournalism. He reviews early apparatuses, including smoked-glass receiving plates and basic spark-gap transmitters, explaining why their crude results failed to satisfy newspaper standards.

Preparing the image The text turns to the mechanical and photographic preparation of the transmitting plate. Photographs are shot through a single-line or cross screen to break the image into discrete strips of varying width, which are then printed onto metal foil using light-sensitized bichromated glue.

Receiving the signal Martin details the electrical and optical methods used to turn incoming wireless pulses back into light marks on photographic film. He examines selenium cells, liquid carbon-bisulphide tubes under magnetic fields, and cathode-ray deflection inside X-ray tubes.

Introducing the telephograph The author reveals his refined system designed for long-distance commercial use, featuring a specialized relay and a light-shutter apparatus. He outlines a precise synchronizing mechanism that brings the sending and receiving drums into lockstep before transmission begins.

Practical optics and laboratory notes The book closes with hands-on instructions for building lined screens, balancing chemical baths, and selecting film speeds. A dedicated optical appendix explains lens focal points, conjugate foci, and techniques for eliminating spherical aberration.

The People

Because this is a technical monograph rather than a work of fiction, its characters are the real-world inventors, experimenters, and foundational scientific concepts driving the field forward.

• Marcus J. Martin: The author and lead experimenter. He seeks a simple, fast, and commercially viable method for sending photos over standard wireless infrastructure. Frustrated by the inertia and slowness of early apparatuses, he designs original relays, optical light-shutters, and the telephograph system.
• Professor Arthur Korn: A prominent rival pioneer in photo-telegraphy. Korn seeks reliable picture transmission by using undamped continuous waves, selenium cells, and high-frequency alternators to short-circuit transmitter inductances.
• Hans Knudsen: An early inventor who made the first practical attempt at wireless image transmission in 1908. Knudsen sought a direct mechanical solution using smoked glass plates and vibrating needles, though his system proved too crude for commercial print reproduction.
• The Wireless Experimenter: The intended reader and ambitious amateur technician. This figure wants to build working radio-photographic apparatuses but faces high costs, scarce documentation, and complex chemical and optical hurdles.

In Its Own Voice

"The wireless transmission of photographs has, no doubt, a great commercial value, but for any system to be commercially practicable, it must be simple, rapid, and reliable..."

Context: Martin introduces the strict economic and technical criteria required for photo-telegraphy to succeed in newsrooms.

"Synchronising and isochronising the two machines are the most difficult problems that require solving in connection with wireless photography..."

Context: The author highlights the primary mechanical hurdle preventing clear image reproduction over long distances.

"A properly exposed and developed negative should not require any reducing or intensifying."

Context: Martin gives direct laboratory advice to experimenters preparing line negatives for printing onto metal foil.

What It's Really About

Beneath its diagrams, chemical formulas, and workshop instructions, the book explores the fundamental challenge of converting continuous visual reality into discrete, transmittable data. Martin grapples with the physical limits of speed, mechanical inertia, and electrical signal degradation. The text wrestles with how to break an image into quantifiable bits—via line screens, stylus contacts, and timed wave bursts—and accurately reassemble those bits miles away without human error. It also captures the democratization of early twentieth-century science, arguing that dedicated amateurs working in small laboratories could solve major engineering problems through careful measurement, optical understanding, and chemical precision.

Why Read It Today

Wireless Transmission of Photographs offers a fascinating historical look at the ancestors of modern digital imaging, fax machines, and television. Readers who enjoy technical history, vintage radio electronics, or early photographic processes will appreciate Martin's meticulous clarity and hands-on tone.

Reading the book feels like sitting at a 1919 workbench beside a patient master craftsman. The prose is clear, direct, and completely free of modern jargon, grounded in the tangible reality of battery circuits, brass drums, optical lenses, and bichromated glue.

The reader must navigate period-specific technical language, obscure chemical names, and mathematical equations regarding lens focal lengths and light angles. The book assumes a reader willing to engage with mechanical blueprints and shop math. Yet for those intrigued by how human beings first learned to send pictures flying through the air on invisible waves, Martin's treatise remains a lucid and illuminating historical document.