1 / The dark room:
“When the image of illuminated objects penetrate through a small hole in an apartment very dark, and you place a white paper at some distance from the hole, the dark side, you see on paper all the objects with their own forms and colors but in reverse. This occurs under the intersection of the rays. ”
This description of the “dark room” was given to the 16th century by Leonardo da Vinci. Thus, the inventor had discovered the optical principle of the camera, three centuries before the first photo.
The use of the camera obscura became widespread during the course of the 17th century. It was used mainly by designers, which layer on paper the image projected through the small hole.
It was then discovered a chemically sensitive to light, designed to replace the paper receiving the image directly and permanently fixing it. The Charles French and English Wedgwood and Davy it applied it, the first successfully set silhouettes, the other obtained images that remained visible within minutes, and disappeared.
2 / Inventors:
It is a French, Niepce, who invented photography in defining for the first time and in a sustainable manner, the images. He used a glass plate, covered with bitumen of Judea, insoluble substance to light. The oldest known photograph, made by Niepce, dates from 1822 and represents a table spread in his garden; 8 hours laying in the sun were needed to get it. In 1829, Niepce associated with the painter Daguerre. They worked separately for four years by communicating the results of their research. But in 1833, Niepce died following an attack, alas too soon, to enjoy the results of its work. For 6 years, Daguerre continued his research alone.
3 / The daguerreotype:
On January 7, 1839, satisfied with his photographic process, he decided to make a presentation at the Academy of Sciences by asking the teacher to present Arago to the process for him. The result was a success. The photographs known as “daguerreotypes” by the inventor was in fact discussed with enthusiasm.
Only in August 1839 that Daguerre published the technical details of his invention:
The sensitive surface was characterized by a layer based on silver iodide, but a comparable product more efficiently to those who had used Davy and Wedgwood. To fix the image, it was discovered that the fundamental element of the fixer photographs, the sodium thiosulphate, the atoms could dissolve the photosensitive silver compounds before they were impressed (amazed) by the light and changed into visible images. However, the thiosulphate did not dissolve the atoms impressed. This discovery allowed him to immerse the image impressed in a bath and stop any chemical reaction before the action of light comes into play and erase the image. Besides fixing, Daguerre’s process was different from modern methods. The daguerreotype used a copper plate with the silver surface, polished. By placing silver side underneath, on top of a container of iodine vapors and is rendered sensitive. These vapors are combined with silver to produce silver iodide photosensitive. Exposed, the plate recording a latent image invisible. The development is done by placing the plate face impressed below, in a second box, this time containing a bowl of mercury, which is heated. The mercury vapor atoms are combined with silver iodide exposure. Where the light rays have reached the plate, mercury engendered an alloy based on silver. This method showed clear areas of the picture while the unexposed areas by light showed dark areas.
4 / calotype:
In 1841, the English Fox Talbot patented a process of his invention, he called “calotype” and was the forerunner of the current processes. While the daguerreotype gave a single positive test, the calotype gave a negative allowed to take more positive. The availability of unlimited number of events led to the final triumph of the calotype daguerreotype.
5 / The creator of the film camera:
During the 50 years that followed, photography, although widespread, requires a lot of patience and a fairly bulky equipment. It was an American industrialist George Eastman, who first proposed to manufacture a device easy to handle, thus photography to everyone. He had the idea to equip the aircraft with a roll with a film on paper, which allowed 100 to take successive pictures. When the entire roll was used, sent his amateur camera to the Eastman plant, near New York, then the exposed film was manipulated in the darkroom and replaced with a new film, the camera was then reloaded sent back to its owner that could take another 100 photos.
Later, Eastman, a packaging system manufactured that allowed the roll out of the device in the light of day, so fans could make their own manipulation.
To make the aircraft more commercial, advertising Eastman sought a name easy to remember and drawing attention: it was inspired by the noise produced when a plug: “pop-tock”, and gave him the name “Kodak.”
The success was immediate: anyone could buy a camera for a small fee and take the pictures of his choice. Photography had become universal.
6 / The director of the small format:
Rolls of film, Kodak invented by the firm were quite broad and could be used for large appliances. A German engineer, Oscar Barnack, which has made 1907 ascents in the mountains with a material that he found too cumbersome decided to make a device that is small and high precision.
This required having a small size camera, very sensitive and able to give subsequent expansions valid.
For years, Barnack tried to make a small device with all parts needed to shoot and easy to winding the film on the reel.
In 1924 appeared the first “Leica” weighing just 500 grams and up to 36 views on a 35mm feature film: in the total width of the film, the actual width of the image is actually 24mm, giving the length of the two images of the film, we got 36mm. Each of the views of the photographic film when measured 24 mm 36 mm.
The success of Leica was also considerable. The small size of the Leica and the great price of small rolls of movie film, combined with a high precision technique, did adopt Barnack’s invention as the current model cameras.
7 / The Polaroid:
Since the devices have greatly modernized and competition is increasingly fierce. Indeed, the Japanese aircraft, excellent qualities, however, are sold cheaper than the European aircraft.
The Americans come to market with a new system, the Polaroid:
He demanded 10 years’ work by a team of American chemists, as well as $ 250 million for its manufacture. This new device called the “X-70″ was developed by Dr. Edwin Land, president of the firm and its employees. This is a revolutionary device whose essential characteristic is to eject a snapshot immediately after the shooting, and growing (in color) in under 4 minutes in the open air.
Unlike the usual instant-film, the cliché out “clean” of the device without the need to proceed with the launch of the negative of the unsafe final test. Thus, while the first view is developed, it has the option of taking other pictures (2 images every 3 seconds).
The emulsion itself is composed of 17 layers with a total thickness not exceeding
3 mm. Both products play a key role: an alkali (potash) and a white pigment, based on titanium dioxide. This dye was chosen because of its singular property of turn black in a strongly alkaline and acidic conditions become clear. It is thus formed in the presence of alkali, an opaque veil that acts as a darkroom. The alkali also aims to penetrate the deep layers and dissolve developing dyes. Pigments, stainless or not captured, are then free to migrate to the surface. Within minutes, a correct grade dyes is deposited on the receiving surface and a fixer stops the movement of dyes that appear on the surface of the image. For all these reactions, the alkali is slowly gnawing a “barrier” plastic whose thickness was calculated to slow the time it takes, the advance of the alkali into an acid layer. This achievement, potash is instantly neutralized the opacifying layer cleared and all the chemical activities are suspended. The cycle is completed and the picture can finally be held and visualized after drying.