How the Camera Was Invented — Forming an Image and Keeping One Are Two Different Problems

In 1826 or 1827, at a country house in Burgundy, France, Nicéphore Niépce set a pewter plate by an attic window. He had coated the plate with a thin layer of bitumen of Judea, a petroleum-derived black substance. Then he waited. The long-accepted estimate for the exposure is eight hours, though recent researchers argue it more likely took several days.^[1] When he finally removed the plate, it carried a faint image of the barn roof and trees across the courtyard. Known today as “View from the Window at Le Gras,” this plate is recognized as the oldest surviving photograph in the world.^[1]

Here is the strange part. The device that projects an outdoor scene onto a surface — the camera obscura — had already existed for hundreds of years before Niépce was born. Painters used it to study perspective, and scholars used it to observe solar eclipses safely. So why did photography not arrive until the 19th century, and even then only through the hands of a stubborn chemical experimenter like Niépce? The truly hard problem in inventing the camera was never forming an image. It was capturing that image and keeping it from disappearing.

The Half That Already Existed: The Camera Obscura

When light passes through a small hole, it projects an inverted image of the outside world onto the opposite wall. This phenomenon had been known since antiquity. But the first person to systematically explain it as an optical principle was Ibn al-Haytham (known in Latin as Alhazen), a scholar active in 11th-century Cairo. Using the fact that light travels in straight lines, he worked out geometrically why a pinhole image appears upside down, and his writings on the subject went on to shape European optics for centuries.^[2]

By the 16th century, the camera obscura had moved out of the scholar’s study and into the painter’s workshop. It became known that fitting a lens into the hole made the image much brighter and sharper, and portable boxes and even tent-like versions soon appeared. Painters used the device to transfer perspective and shading accurately onto canvas. Whether the 17th-century Dutch painter Johannes Vermeer used a camera obscura remains debated today. Some scholars argue that the distinctive blurring of light and perspective distortions in his paintings are traces of an optical device,^[3] while other art historians counter that this level of realism was well within reach of pure observation and training.^[3] Whichever side is correct, it is clear that the device was a widely used aid in European painting after the Renaissance. The precision lens-grinding techniques that underpinned all of this later split off into telescopes and microscopes, developments covered separately in The History of the Telescope and The History of the Microscope.

What matters here is that the camera obscura already worked on almost the same principle as photography: a dark box, a small hole or lens, and an image of the outside world projected onto the opposite surface. The only thing missing was a surface that could capture that image on its own. Painters filled that gap with their own eyes and hands. The remaining problem was how to make light itself etch the image onto a surface, without a human eye or hand in between.

The Missing Half: The Chemistry of Fixing an Image

The person who first attempted this was not a painter but a chemist. In 1727, the German professor of medicine Johann Heinrich Schulze discovered that a mixture of silver nitrate and chalk stayed unchanged in the dark but turned black when exposed to light. He first placed the mixture in an oven and heated it, and nothing happened — which let him confirm that heat was not the cause of the darkening.^[4] This was the first experimental evidence that light itself could drive a chemical reaction. But Schulze never applied the reaction to recording an image. He went only as far as attaching paper stencils shaped like letters to the bottle, showing that only the exposed portions turned dark.

Late in the 18th century, Thomas Wedgwood, son of the British potter Josiah Wedgwood, took the idea a step further. He laid leaves and drawings on paper or leather soaked in silver nitrate, exposed them to light, and succeeded in etching their outlines onto the light-sensitive surface. In experiments conducted with the chemist Humphry Davy, the two even tried to capture images projected by a camera obscura onto sensitized paper.^[5] But they ran into a decisive wall. An image would form, but if it was exposed to light any further, the entire sheet would darken and the image would vanish. They had not found a way to fix the image — to wash away the silver salts that had not reacted while leaving the exposed ones in place. In a paper published in 1802, Davy candidly admitted this failure and expressed hope that future researchers would solve it.^[5]

To sum up: the device for forming an image already existed, and it was already known that light could darken certain chemicals. So why did photography still take another twenty-odd years to appear? Because the problem was never making an image — it was holding on to the image once it was made. Wedgwood and Davy never found the key to that last lock.

Niépce’s Heliography: An Exposure of Patience

Nicéphore Niépce was less a chemist than an inventor. While trying to improve lithographic printing, he noticed that bitumen hardens when exposed to light and becomes insoluble in solvent.^[1] Unlike silver salts, bitumen becomes more stable in the areas that receive light, so once the unexposed portions are washed away with a solvent like lavender oil after exposure, the image simply remains. In principle, this was a way to fix an image permanently.

Sometime between 1826 and 1827, Niépce set a pewter plate coated with a thin layer of bitumen behind a camera obscura, pointed toward the view outside his window. How long the exposure actually took is still debated. The long-accepted estimate was eight hours, based roughly on the arc the sun traces over a day. But researchers who later re-examined Niépce’s notes and reproduced the process with the same materials have suggested that hardening the bitumen enough to leave a visible image would have required several days of cumulative exposure.^[1] Either way, the exposure was clearly extraordinarily long — the finished image shows both sides of a building lit simultaneously, a trace of the sun’s movement across the sky over that time.

Niépce’s achievement was historically decisive but had almost no practical use. An exposure lasting hours or days could not capture a moving person, let alone a passing cloud. He went on to partner with the Parisian stage designer Louis Daguerre to work on shortening the exposure time, but he died suddenly of a stroke in 1833 and never lived to see the results.^[6]

The Daguerreotype and the Calotype: A Fork Between Openness and Patents

After Niépce’s death, Daguerre carried the research forward alone and arrived at an entirely different chemical process. A silver plate was exposed to iodine vapor to form a light-sensitive layer of silver iodide, then exposed to an image through the camera, developed with mercury vapor, and fixed with a salt solution (later replaced by sodium thiosulfate). Exposure times shrank to a matter of minutes. In 1839, the French Academy of Sciences formally announced this process, the “daguerreotype.”^[7]

This is where the paths of photography’s future split in a decisive way. The French government bought the patent to the daguerreotype process from Daguerre and Niépce’s son, in exchange for lifetime pensions, and presented it “as a gift from France, free to the world.”^[7] There was one exception. Just days before the French government’s announcement, Daguerre’s agent had quietly registered a separate patent in Britain alone. As a result, anyone in Britain and its colonies who wanted to use the daguerreotype still had to pay royalties — Britain was effectively the only country excluded from the free gift.^[7] Everywhere else, the technology could be used by anyone without royalties, and the daguerreotype spread rapidly across Europe and the United States.

At roughly the same time, the British scientist William Henry Fox Talbot completed an entirely different approach. He coated paper with a light-sensitive substance to first produce a tonally reversed “negative” image, then pressed this negative against another sheet of sensitized paper and passed light through it to obtain a “positive” print with the tones restored to normal. He called this the “calotype” and patented it in 1841.^[8] Where the daguerreotype produced a single, unrepeatable original image on a silver plate, the calotype allowed any number of copies to be printed from a single negative.

The outcome was ironic. The daguerreotype produced far sharper images and was overwhelmingly popular at first, but because it was an open technology with no patent restrictions, there was little incentive to improve it further. The calotype, by contrast, was locked up by Talbot’s patent within Britain but could be used freely everywhere else, and photographers in France and other countries went on to refine it.^[8] In the end, it was not image quality but reproducibility that decided the future of photography. The structure of pulling as many prints as desired from a single negative became the prototype of the “negative-positive” process that, via the wet collodion process and dry plates, continues to this day. The daguerreotype left behind one-of-a-kind relics. Talbot’s method left behind the essential condition of photography itself: an image that could be copied without limit.

From Cumbersome to Mass Market: From Collodion to Kodak

The wet collodion process that appeared in the 1850s greatly improved both image quality and exposure speed, but at a cost: photographers had to haul an entire portable darkroom with them. A glass plate had to be coated with the sensitizing solution, and both the shooting and the developing had to be finished while it was still wet. The arrival of dry plates in the 1870s solved this problem. Photographers could now buy pre-manufactured dry plates from a shop, load them into a camera whenever needed, take the picture, and bring the plates to a developing shop later. Shooting and developing had finally been separated in time.

American readers in particular will recognize this era from a different angle: the battlefield. During the Civil War (1861–65), Mathew Brady organized teams of photographers — including Alexander Gardner and James Gibson — who hauled the same wet-collodion darkroom wagons described above onto active battlefields, an operation soldiers reportedly nicknamed the “whatizzit wagon.” When photographs from Antietam went on display at Brady’s New York gallery in October 1862, the New York Times wrote that he had “done something to bring home to us the terrible reality and earnestness of war.”^[15] It is often cited as the moment photography stopped being confined to studio portraits and landscapes and became a tool for showing a mass audience, many of whom had never been near a front line, what war actually looked like — a role news photography has played in English-language media ever since.

The person who pushed this separation into an entirely new business model was George Eastman. He developed flexible roll film and, in 1888, released a camera under the name “Kodak.” Preloaded with enough film for 100 exposures, the camera could simply be mailed back to the factory in its entirety once the roll was finished. The company developed and printed the film, reloaded the camera with fresh film, and mailed it back.^[9] Eastman’s advertising slogan became one of the most iconic lines in the history of photography: “You press the button, we do the rest.”^[9]

This shift meant far more than a simple convenience upgrade. Until then, photography had belonged to specialists who understood chemistry and optics. Kodak completely separated the act of taking a picture from the chemical process of developing and printing it, turning shooting into something anyone could do. For the first time, the person who took the photograph and the person who chemically produced it were different people. This division of labor became the basic structure of the photography industry for more than a century afterward.

In the early 20th century, Oskar Barnack, an engineer at the German firm Leitz, designed a compact camera that repurposed 35mm film — until then used only for movies — for still photography. The prototype he built around 1913–14, known today as the “Ur-Leica,” led to the commercially released Leica I in 1925.^[10] Compared to the large, heavy dry-plate cameras of the time, the Leica fit in one hand, and a single roll of film could capture 36 exposures in succession. This portability, later combined with the single-lens reflex (SLR) design that let photographers see through the lens itself via a mirror and prism, opened up the genres of the snapshot and photojournalism — photographers moving freely through streets and events to catch a moment as it happened.

Around this same period, an entirely different branch of moving images produced by cameras — motion pictures — was growing alongside still photography. That story is told separately in The Birth of Cinema. This article stays focused on the single still image.

Instant Photography and Polaroid: Eliminating the Darkroom

If Kodak drove mass adoption by separating shooting from developing, another figure pushed mass adoption in the opposite direction. The American physicist Edwin Land began researching instant-development technology after a famous incident in 1943 in which his young daughter reportedly asked him why she could not see a photograph right away.^[11] In 1948, Polaroid released an instant camera that pressed the film together with developing chemicals inside the camera body at the moment of exposure, producing a finished photograph in about a minute. It was a different answer to the same problem Kodak had solved in its own way: how to make the chemical process disappear from the user’s view entirely.

The CCD and Kodak’s Paradox: The Shift to Digital

In 1969, Willard Boyle and George Smith of Bell Labs in the United States invented the charge-coupled device (CCD). This semiconductor could convert light into an electrical signal and store it, and the two researchers received the Nobel Prize in Physics in 2009 for the achievement.^[12] Then in 1975, Steven Sasson, a young engineer at Kodak, used this CCD technology to build the world’s first digital camera prototype. Weighing 3.6 kilograms and recording black-and-white images onto cassette tape, the device took 23 seconds to capture a single photograph.^[13]

Here lies one of the most famous twists in the history of photography: the company that built the world’s first digital camera was, in the end, undone by the very technology it had invented. The story that Kodak’s executives reacted to Sasson’s prototype by saying it was “cute” but told him not to tell anyone about it is frequently cited as a symbolic case of a company protecting its film business at the cost of its own future.^[13] Kodak did, in fact, file for bankruptcy protection in 2012.

Before accepting this narrative at face value, though, there is something worth noting. Business history researchers point out that the popular story that “Kodak ignored digital” is an oversimplification.^[14] In reality, Kodak invested billions of dollars in the digital camera business through the 1990s and early 2000s, and at one point even led the United States in digital camera sales.^[14] A more persuasive explanation is that Kodak’s collapse had less to do with the digital camera itself than with the sudden disappearance of its overwhelmingly profitable film-developing business, compounded by smartphones swallowing up the digital camera market as well.^[14] What Sasson’s invention symbolizes is not so much the failure of a single company as the structural shock felt across an entire industry — one built for over a century on fixing images chemically — as it shifted onto semiconductors.

Optics Waited, Chemistry Arrived Late

Ibn al-Haytham worked out the principle of the pinhole image in the 11th century. Painters were using the camera obscura to render landscapes hundreds of years after that. Yet the chemical method for fixing that image onto a surface arrived only centuries later still, and only after chemists repeatedly failed while wrestling with dark stains on silver plates. What completed the invention of the camera was not the box and the lens, but the stubborn chemical experiments that finally found a way to freeze a light-sensitive substance at the instant it reacted. And it would take nearly another 150 years for that method to move from silver salts to semiconductors.