Photography
Although it appeared in the 19th century, photography began to be invented in antiquity, when the principle of the “camera obscura” was discovered. All you have to do is completely close off a place – from a large room to a can of powdered milk – and then make a small hole. The light passes through the hole and projects an inverted image of what happens outside inside the closed chamber. Even with this principle known for centuries, the main thing was missing for photography: to come up with a way to freeze this image. Official history records two inventors who came up with a solution to this at about the same time: Henry Talbot in England and Louis Daguerre in France. In 1835, Talbot published a paper documenting how he managed to fix images using paper treated with silver chloride, which was then dipped in a salt solution. The result was a negative, that is, it could be copied several times.
Daguerre’s method, officially announced four years later, captured the images on a thin copper plate coated with silver salts, which then received mercury vapor to ensure fixation. The result was an already positive image that could no longer be copied. Despite this limitation, the quality of the photographs obtained by the so-called “daguerreotype” was superior to those taken by Talbot, so much so that Daguerre’s method was successful for many decades, until the improvement of new negative exposure techniques. What the official story does not tell, however, is that in 1833 photography may have been invented in Brazil, with a different method, by Antoine Hercule Florence, a Frenchman who lived here for many years. After several experiments – which even included the use of urine to fix images – Antoine developed a chemically treated glass plate that captured the image and could then transfer it to paper.
This feat remained little recognized for decades until historian Boris Kossoy, from the University of São Paulo (USP), revealed the feat in the book 1833: The isolated discovery of photography in Brazil. “Antoine used the process to print and copy images, as he had been working on a printing system for a long time,” says Boris. Now, in addition to the airplane, we Brazilians can also lay claim to the invention of photography. me
Two cameras that help tell the story of this invention: on the left, a Kodak from 1922; right, a 1965 Rolleiflex
Story revealed The first processes for fixing images appeared in the mid-19th century.
official pioneers
In the first decades of the 19th century, Frenchman Louis Daguerre created the daguerreotype, perfecting research by his colleague Nicéphore Niépce. He officially divulges his method in 1839, four years after the Englishman Henry Talbot made public the negative development process. At that time, taking a single photograph takes up to 30 minutes.
glass negative
In 1851, an English sculptor, Frederick Scott Archer, discovered the wet plate development process (also called colloid) and revolutionized photography. Negative glass plates were superior in quality to daguerreotypes and, for the first time, allowed multiple paper copies of a photograph to be produced.
sensitive gelatin
In 1871, English physicist Richard Leach Maddox creates a gelatinous solution of silver bromide. His “dry plate” method did not require the plates to be developed on the spot, as with the colloid, in addition to being 60 times more sensitive. Gelatin could be applied on paper and on transparent films. It’s the beginning of modern photography
camera for everyone
With the plate dry, portable cameras multiply. In 1886, the American George Eastman starts selling a machine with which the person took pictures on a practical roll of film and did not need to mess with development. The slogan for Eastman’s company, Kodak, was: «You push the button, we’ll do the rest.» Photography is popular
colorful idea
In 1908, the French brothers Auguste and Louis Lumière, the same ones who invented cinema, created the first color photography process, Autochrome, superimposing three transparent plates. Thanks to the use of filters, each one recorded only one primary color (red, yellow and blue) and the final result was a color image.
instant smile
The American Edwin Land astounds the public in 1947 by developing an instant film, which reveals itself at the time the picture is taken. In 1963, he presents the same process, only now in color. Land and his company, Polaroid, made their fortune selling millions of instant cameras.
Film for what?
The world of photography would not change much until the digital camera revolution. In 1986, Kodak creates an electronic sensor, which makes up the “film” of the digital camera, capable of registering more than 1 million points of light, enabling the photography of the new era, which would explode in earnest in the 90s.
Optical and chemical trick Silver microdots draw the scene projected by a lens
1. Cameras use the darkroom principle. But in place of the hole that allows light to enter the closed container, there is a lens, which increases the brightness of the image projected onto the photographic film.
2. This lens, which is convex, focuses the light rays emitted by the object to be photographed in a single point. The image of the object will then be projected onto the machine’s film in an inverted manner.
3. Photographic films contain silver salts, a transparent substance. When exposed to light, the silver that composes these salts becomes visible, in the form of millions of dark dots that draw the photograph taken
Read too:
– How does holography work?
– How is the production of a film?