The Birth of Portable Photography

The wet collodion process, for all its power, chained photographers to the darkroom. Every plate had to be coated, exposed, and developed while still damp — a practical window of about ten minutes. Landscape photographers dragged portable darkrooms into the wilderness; portrait studios reeked of ether and collodion fumes. Photography was the domain of specialists, not something an ordinary person could pick up and do. The decades between 1870 and 1930 changed all of that. In that span, a series of innovations — dry plates, flexible film, simple cameras, and miniature formats — took photography from a professional craft to a personal act. The camera went from a piece of scientific apparatus to something you could slip into a coat pocket.

The Dry Plate Revolution

The crucial first step was freeing photographers from the wet darkroom. In 1871, an English physician named Richard Leach Maddox published a short paper in the British Journal of Photography proposing that gelatin could replace collodion as the medium for carrying silver salts on a glass plate. Maddox was motivated partly by health concerns — the ether fumes from collodion aggravated his respiratory condition — but his idea had far-reaching consequences.

Maddox's original gelatin emulsions were slow, barely faster than wet collodion. But other experimenters refined the formula. Charles Bennett discovered in 1878 that prolonged heating of the gelatin emulsion during preparation (a process now called ripening) dramatically increased its sensitivity to light. By the early 1880s, factory-produced gelatin dry plates were available that were several times faster than wet collodion and could be stored for weeks or months before use. The photographer no longer needed to prepare plates on the spot. Plates could be manufactured in a factory, purchased from a shop, loaded into plate holders in a changing bag, carried into the field, exposed whenever the moment demanded, and developed at leisure — hours, days, or even weeks later.

This single change restructured the entire practice of photography. The dry plate separated the act of taking a photograph from the act of developing it. For the first time, you did not need to be a chemist to be a photographer. You only needed to point the camera and open the shutter. The chemical work could be delegated to someone else or postponed indefinitely.

George Eastman and Roll Film

George Eastman was a young bank clerk in Rochester, New York, when he became fascinated by photography in the late 1870s. He purchased a wet plate outfit and found the process — the chemicals, the glass plates, the heavy tripod — maddeningly cumbersome. Eastman saw a commercial opportunity: if he could manufacture dry plates more efficiently than anyone else, there was a growing market of amateur photographers eager to buy them.

Eastman began experimenting with gelatin emulsion coating machines, and by 1880 he had patented a machine for coating glass plates in quantity. He founded the Eastman Dry Plate Company (later the Eastman Kodak Company) and began selling factory-made plates. But glass plates, even dry ones, were heavy, fragile, and bulky. Each plate had to be loaded individually into a plate holder. Eastman wanted something lighter and more practical.

In 1884, Eastman and his camera designer William Hall Walker patented a roll holder that used a long strip of paper coated with gelatin emulsion, wound on a spool. After exposure, the paper backing was stripped away and the gelatin emulsion film was transferred to a glass plate for printing. The system was awkward and unreliable, but it proved the concept: a continuous strip of flexible material could replace individual glass plates.

Eastman's crucial breakthrough came in 1888 with the introduction of the original Kodak camera. It was a simple wooden box, pre-loaded at the factory with a roll of flexible film sufficient for 100 circular exposures. The camera had a fixed-focus lens, a single shutter speed, and one aperture. The photographer pressed a button to release the shutter, then turned a key to advance the film. There were no settings to adjust, no plates to load, no chemicals to mix. When all 100 exposures had been made, the photographer mailed the entire camera back to Eastman's factory in Rochester. There, technicians unloaded the film, developed it, made prints, loaded a fresh roll of film into the camera, and mailed everything back. The famous slogan said it all: "You press the button, we do the rest."

The original Kodak camera cost $25 — a substantial sum in 1888, roughly equivalent to $800 today — and reloading cost $10. It was not a mass-market product. But it was a radical proof of concept. For the first time, the camera was a consumer device, not a piece of laboratory equipment. The photographer needed no technical skill whatsoever. Eastman had not merely simplified photography; he had reinvented it as a consumer service.

The Brownie and the Democratization of Photography

The real revolution came twelve years later. In February 1900, Eastman Kodak introduced the Brownie camera, a cardboard box camera covered in imitation leather, fitted with a simple meniscus lens and a rotary shutter. It produced 2-1/4 inch square exposures on a new film format: 117 roll film. The price was one dollar. A six-exposure roll of film cost fifteen cents.

One dollar. At that price, almost anyone could afford a camera. The Brownie was marketed specifically to children, with advertising featuring illustrations by the Canadian artist Palmer Cox, whose "Brownie" characters — mischievous elf-like sprites — gave the camera its name. But adults bought them too, in enormous numbers. Kodak sold over 150,000 Brownie cameras in the first year alone.

The Brownie did more than sell cameras. It created a new cultural phenomenon: the snapshot. Before the Brownie, photographs were deliberate, formal affairs — people went to studios, sat still, and posed. After the Brownie, photographs became casual, spontaneous, personal. People photographed their families at picnics, their children playing, their dogs, their gardens, their holidays. The snapshot album became a fixture of domestic life. Photography was no longer something done to you by a professional; it was something you did yourself, for yourself, whenever you wanted.

The Rise of Roll Film Formats

The Brownie's success launched a proliferation of roll film formats. Eastman Kodak introduced new film sizes at a rapid pace to accommodate cameras of different sizes and ambitions. In 1901, Kodak released 120 film — a format that would prove to be one of the most durable in photographic history.

120 film is a strip of photographic emulsion on a flexible base, wound with a paper backing onto a flanged spool. The paper backing serves multiple purposes: it protects the film from light during loading and unloading, it provides a surface for frame numbers printed on the back (visible through a red window on the camera body), and it keeps the film wound tightly on the spool. The film strip is approximately 62mm wide, and the length of each frame depends on the camera: 6x4.5cm, 6x6cm, 6x7cm, 6x9cm, and other formats are all shot on the same roll of 120 film. A 6x6 camera gets 12 exposures per roll; a 6x4.5 gets 15 or 16; a 6x9 gets 8.

Remarkably, 120 film is still manufactured today, well over a century after its introduction. It remains the standard medium format film and is the format used by every twin-lens reflex camera ever made. When you load film into a TLR, you are using a format that dates to 1901. Other roll film formats — 127, 620, 616, 828 — came and went over the decades, but 120 endured.

Oskar Barnack and the Birth of 35mm

While roll film was making photography accessible to the masses, a different revolution was brewing inside a German optical factory. Oskar Barnack was a development engineer at Ernst Leitz in Wetzlar, a company that manufactured microscopes and other precision optical instruments. Barnack was an avid amateur photographer, but he suffered from asthma that made it difficult to carry the heavy plate cameras and tripods that serious photography still demanded. He wanted a small, lightweight camera that could produce high-quality images.

Barnack's insight was to repurpose 35mm motion picture film — a format introduced by Thomas Edison and William Kennedy Laurie Dickson in the early 1890s for the Kinetoscope, and standardized for cinema projection by the early 1900s. Cine film was 35mm wide with perforations along both edges. In a movie camera, each frame was roughly 18x24mm, oriented with the long side running perpendicular to the length of the film strip. Barnack turned the film sideways: instead of running it vertically as in a movie camera, he ran it horizontally and doubled the frame size to 24x36mm, producing a still image that was much larger than a single movie frame.

In 1913 or 1914, Barnack built a prototype — later known as the Ur-Leica — that used this doubled-frame 35mm format. It was a tiny camera by the standards of the day, fitting easily in one hand. The outbreak of World War I delayed development, but Ernst Leitz's son, Ernst Leitz II, made the bold decision to put the camera into production. The Leica I (for Leitz Camera) was introduced commercially at the Leipzig Spring Fair in 1925.

The Leica was a precision instrument, beautifully made, with a retractable lens and a focal-plane shutter. It was expensive — well beyond the reach of casual snapshooters — but it appealed enormously to serious photographers and photojournalists. It was small enough to carry unobtrusively, quick to use, and its 36-exposure film rolls meant you could shoot prolifically without reloading. The Leica enabled a new kind of photography: candid, spontaneous, shot on the street and in the thick of events. Henri Cartier-Bresson, André Kertész, Robert Capa — the founders of modern photojournalism — all used Leicas.

The 35mm format soon attracted competitors. Zeiss Ikon launched the Contax in 1932, and by the mid-1930s, 35mm cameras were being manufactured by companies across Germany and Japan. Kodak introduced pre-loaded 35mm film cartridges (the now-familiar canister with a protruding film leader) in 1934, making the format accessible beyond the Leica system. By the 1950s, 35mm had become the dominant format for serious amateur and professional photography.

A Landscape of Formats

By the 1930s, photographers could choose from a bewildering variety of film formats, each with its own cameras, its own trade-offs between image quality and convenience:

• Large format (4x5 and 8x10 inch sheet film) — the direct descendant of the glass plate, used with view cameras on tripods. Maximum image quality, minimum portability. The domain of landscape, architectural, and commercial photographers. Ansel Adams hauled his 8x10 into Yosemite; Edward Weston used a 4x5 for his luminous still lifes.
• 120 roll film — medium format, used in a wide variety of camera types. The 6x6cm square format became the standard for TLR cameras; 6x4.5, 6x7, and 6x9 were used in folding cameras and later in SLR-style medium format systems. An excellent balance of image quality and portability.
• 127 roll film — a smaller roll film (46mm wide) used in compact cameras like the Vest Pocket Kodak, popular from 1912 through the 1960s. Produced 4x4cm or 4x6.5cm frames. Now largely obsolete, though a few specialty manufacturers still produce it.
• 620 roll film — the same film width as 120 but wound on a thinner spool, introduced by Kodak in 1931 for use in their own cameras. A transparent attempt to lock customers into the Kodak ecosystem. No longer manufactured, though 120 film can be respooled onto 620 spools.
• 35mm (135 format) — the smallest serious format, producing 24x36mm frames. Thirty-six exposures on a standard roll. Fast to use, compact cameras, the workhorse of photojournalism and street photography. Eventually became the world's dominant film format.

From Professional Tool to Personal Device

The transformation that occurred between 1871 and 1935 is difficult to overstate. In 1871, a photographer was essentially an itinerant chemist: someone who mixed emulsions, coated plates, and developed images in a darkroom, all as part of the same continuous process. By 1935, a photographer was simply someone who owned a camera. The chemical work had been industrialized, the equipment miniaturized, the skill barrier lowered almost to zero.

This had profound cultural consequences. The photographic record of human life, which before 1888 consisted almost entirely of formal portraits and professional documentation, exploded into the rich, messy, intimate visual culture we know today. Birthday parties, beach holidays, awkward family gatherings, a child's first steps — the entire fabric of personal memory was now captured on film. Photography had become, in the fullest sense, personal.

But even as 35mm cameras grew smaller and roll film cameras grew more sophisticated, one particular camera design was quietly establishing itself as the medium format photographer's ideal companion. It used two lenses instead of one, offered a viewing experience like no other camera before or since, and it would produce some of the most celebrated photographs of the twentieth century. The twin-lens reflex is the subject of our next lesson.