CREDIT WHERE CREDIT IS DUE

The discovery of "mercurializing," as it came to be called, was Daguerre's and Daguerre's alone—and understandably, he wanted full credit for it. In 1837 he drew up a new contract with Isidore Niepce in which he took credit for the new process, but gave Joseph Niepce credit for the old process. Isidore Niepce objected to the terms, but had little choice in the matter—he had not participated in Daguerre's research, did not know how the new process worked, and could not claim credit for it. So he signed.

They made plans to sell both steps of the photographic process to private investors, but when the French Academy of Sciences caught wind of the idea, it persuaded the French government to purchase the rights and give them away free to the entire world... except their traditional rival, England. Daguerre's process was now free of charge for anyone in the world—except the Brits, who had to pay him a royalty.

NOTHING LIKE IT IN THE WORLD

On January 7, 1839, Daguerre went before the Academy of Sciences to show his daguerreotypes and give a description of his process. The assembled scientists were amazed. Images that detailed did not exist anywhere on Earth and were virtually inconceivable to the 19th-century mind. They were so finely detailed that people called them "mirrors with a memory."

The American inventor Samuel Morse was in Paris when the Academy of Sciences published the news of Daguerre's process; Daguerre invited him to view the pictures. Morse described what he saw in a letter home to his brother: The exquisite minuteness of the delineation cannot be conceived. No painting or engraving ever approached it. For example: in a view up the street, a distant sign would be perceived, and the eye could just discern that there were lines of letters upon it, but so minute as not to be read with the naked eye. By the assistance of a powerful lens, which magnified fifty times...every letter was clearly and distinctly legible, and so also were the minutist breaks and lines of the walls of the buildings; and the pavements of the streets.

The effect of the lens upon the picture was in a great degree like that of the telescope in nature.... [It is] one of the most beautiful discoveries of the age.

DAGUERREOTYPE-MANIA

On July 7, 1839, six of Daguerre's daguerreotypes were put on public display in Paris; then on August 19, the full detailsof the photographic process were released to the world. The world's first photography fad started within days, as Parisians descended on the city's lens makers by the thousands to order the equipment that would allow them to make their own daguerreotype images. Eyewitness Marc Antoine Gaudin described the scene:
Opticians' shops were crowded with amateurs panting for daguerreotype apparatus, and [soon] everywhere cameras were trained on buildings. Everyone wanted to record the view from his window, and he was lucky who at first trial got a silhouette of rooftops against the sky.

He went into ecstasies over chimneys, counted over and over roof tiles and chimney bricks, was astonished to see the very mortar between the bricks—in a word, the technique was so new that even the poorest plate gave him indescribable joy. 

YOU HAVE TO START SOMEWHERE

The world's first photograph, the one that Joseph Niepce took in 1827, survives to this day. There is a picture of it in just about every book on the history of photography, but it is almost impossible to make out anything that's in it. If there was nota caption next to it identifying the objects in the scene (a courtyard, a pigeon loft, and the roofs of some buildings), you would never be able to guess what they are.

Clearly, Niepce's heliographic process was flawed. For one thing, the light-sensitive medium he used, bitumen of Judea, was very slow to react, which meant that long exposure times were required to take pictures. Very long exposure times: That first picture required an exposure of more than eight hours, during which time the sun moved most of the way across the sky. So did the shadows, obscuring much of the picture's detail.

Additionally, the sloppy way Niepce smeared bitumen of Judea on his metal plates made the resulting image even blotchier and harder to make out than it would have been otherwise.

ENTER DAGUERRE

Niepce could not solve these problems himself, so he joined forces with a Parisian theater owner named Louis Daguerre, who was also experimenting with photography. Daguerre's motivation: he thought that photography, if it were perfected, could be used to create better scenery for the theater.

In 1829 the two men signed an agreement to work together for 10 years, but unfortunately Niepce died from a stroke 4 years into the partnership. Daguerre tried to continue the work with Niepce's son Isidore, but Isidore was convinced that if he contributed anything, Daguerre would take credit for it, so he refused to do any research on his own.

SERENDIPITY

Daguerre soldiered on by himself, and in 1835 made an amazing — and accidental — discovery. One sunny morning, the story goes, Daguerre polished a silvered copper plate and placed it in a box containing iodine. The iodine combined with the silver in the plate to form photosensitive silver iodide, which was a significant improvement over Niepce's bitumen of Judea. Then he loaded the plate into a camera. 

That morning he set everything up and started his exposure, which he expected to take several hours... but a half hour later the sun disappeared behind some clouds, ruining everything. Daguerre took the plate out of the camera and tossed it into his chemical cabinet so it would be out of the way.
The following morning, when he took the plate out of the cabinet to polish it for reuse, he saw that it contained a very sharp, detailed image of the picture he had tried to take the day before. 

WORTH A THOUSAND WORDS

How did the picture get there? Thirty minutes of exposure was nowhere near enough time to create an image. Daguerre guessed that the short exposure had been enough to create a hidden or "latent" image on the plate, and that one of the chemicals in the cabinet must have "developed" it to the point that it was visible to the naked eye. He tested his theory by taking another 30-minute exposure and leaving it in the chemical cabinet overnight, as well.

Sure enough, the following morning there was an image on the plate. By process of elimination, Daguerre discovered that vapors from mercury, stored in the cabinet, had developed his exposures.

Daguerre made another important discovery: Like Wedgwood and Schulze, he wanted to arrest the photosensitive reaction to stop photographic images from being obliterated from further exposure to light. He solved the problem by soaking his developed daguerreotypes, as he called them, in a saltwater bath to create the first permanent photographic images. (Well, almost permanent: the saltwater did not arrest the photosensitive reaction completely, but it did slow it down enough that daguerreotypes could be viewed in daylight and could even be preserved for many years.)

PAPERWORK

 One man who learned of Schulze's experiment was Thomas Wedgwood, son of the legendary English potter Josiah Wedgwood. Wedgwood thought he could use the process to make duplicates of artwork for his pottery.
He started out by soaking pieces of paper in a solution of silver nitrate to make them photosensitive (sensitive to light). He then laid his sketches on top of these materials and put them out in the sun. The sunlight would shine through the sketch where the paper was blank, but would be blocked where there was ink, creating a reverse, or "negative," image of the original sketch. The experiment worked. Wedgwood became the first person in history to transfer an image onto photosensitive paper.

 Wedgwood might have become the father of photography, but his health was so poor that he had to abandon his research before could reach his next goal: recording the image created by a camera obscura. And like Schulze, he died without figuring out how to arrest the photosensitive reaction so that his images would be made permanent. Even when viewed by candlelight, it was just a matter of time before they disappeared into darkness forever.

FIXING THE PROBLEM

 The next major contributor to the chemistry of photography was a 19th-century French physicist named JosephNicephore Niepce.
Niepce was looking for a way to copy artwork automatically, to avoid having to pay artists to do it. He repeated the experiments of Schulze and Wedgwood and searched for chemicals that would give, him positive images, but finally, after years of failed experiments, gave up on chemicals that change color and started looking for chemicals that harden when exposed to light. That is when his luck began to change.

 Having worked as a printer, Niepce was familiar with "bitumen of Judea," an asphalt compound dating back to the Egyptians and commonly used by lithographers. He knew that when bitumen of Judea was exposed to sunlight, it hardened to the point that solvents would no longer dissolve it. Therefore, he smeared a metal printing plate with the stuff, placed an ink drawing on top of the plate, and left them both out in the sun. Just as he expected, the sunlight passed through the blank paper, striking the bitumen of Judea underneath and causing it to harden. But where the sunlight was blocked by the ink, the bitumen of Judea remained soft and could be washed away with solvents. The result was a perfect copy of the original drawing. Niepce named the process heliography, after helios, the Greek word for "sun," and graphos, "writing."

THE NEXT LEVEL

 Taking his discovery to the next step, one sunny morning in 1827, Niepce smeared some bitumen of Judea onto a printing plate and put it inside a camera obscura. Then he pointed the camera obscura out of an upstairs window of his country home and left it there for most of the day. In the process, he took what historians consider the world's first true photograph.