The first photographic or heliographic procedure was invented by Niépce around 1824. The images were obtained with Judean bitumen, spread on a silver plate , after an exposure time of several days.
In 1829, Niépce associated Louis Jacques Mandé Daguerre in his investigations.
In 1832, they set up, from the residue of the distillation of the lavender essence, a second procedure that produces images with an exposure time of a whole day.
Hippolyte Bayard, 1801-1887
Niépce died in 1833. Daguerre continued to work alone and invented, in 1838, the daguerreotype , the first procedure that included a development stage. A silver plate covered with a thin layer of silver iodide was exposed in the camera obscura and then subjected to the action of mercury vapors that caused the appearance of the invisible latent image, formed in the course of exposure to light.
This development consisted of a great amplification of the light effect, with which the exposure time did not exceed 30 minutes. The fixation was obtained by immersion in water, saturated with sea salts.
Hippolyte Bayard
In July 1839, another Frenchman, Hippolyte Bayard, discovered the means of obtaining positive images directly on paper . A silver chloride coated paper was darkened to light and then exposed in the dark chamber after being impregnated with silver iodide. Exposure time was thirty minutes to two hours.
Fox Talbot, 1800-1877
William Henry Fox Talbot
Always in 1839, the announcement of the invention of the daguerreotype prompted the Englishman William Henry Fox Talbot to resume interrupted research whose beginnings dated back to 1834. In 1841, he patented the calotype, the first negative / positive procedure that allowed the multiplication of the same image thanks to obtaining an intermediate negative on silver chloride paper, made translucent thanks to the wax. As with the daguerreotype, the latent image was then developed, using a chemical, the developer: a solution of gallic acid and silver nitrate. A second sheet of paper also coated with silver chloride was later exposed through the translucent negative to give the final positive.
John Herschell
John Herschell, 1792-1871
In 1839 John Herschell is due to discover the means of fixing images, immersing them in a bath of sodium hyposulfite , the same essential component of current photographic fixatives. The advantages of the calotype were mainly based on the ease of handling the copies on paper and the possibility of multiple reproduction. In rematch, the definition, limited by the presence of the negative paper fibers, could not rival the daguerreotype.
Hippolyte Fizeau
To further reduce exposure time, shorter, brighter focal lenses were created, thus preserving sharpness throughout the image. In 1841, the physicist Fizeau replaced silver iodide with silver bromide whose sensitivity to light is much higher. Nothing more than a few seconds of exposure were enough to obtain a daguerreotype. Then taking portraits became possible.
Abel Niépce de Saint-Victor, replaces paper with glass.
Abel Niépce de Saint-Victor
In order to improve the transparency of the negative calotype, Abel Niépce de Saint Victor, Niépce’s cousin, discovered in 1847 how to replace paper with glass . In order for the silver bromide to adhere to the glass, he had the idea to mix it with the albumin (the white of the egg). Although slightly contrasted, the images became extremely accurate, forcing opticians to fine-tune even more efficient lenses.
Frederick Scott Archer
Scott Archer
In 1851, the English Scott Archer replaced albumin with collodion based on gunpowder cotton. The black and white images obtained by this procedure achieved a quality never obtained again. With the drawback that the taking had to take place while the plate was still wet and that the developing had to be done immediately afterwards.
Richard Maddox, 1816-1902
Richard Maddox and Charles Bennet
In 1871, another Briton, Richard Meaddox, remedied this problem by replacing Collodion with gelatin , a procedure perfected by Charles Bennet who demonstrated that gelatinized plates acquired great sensitivity when one kept them for several days at 32 ° C. Gelatin plates -bromide could not only be stored before use, but its sensitivity was such that the exposure did not exceed a fraction of a second.
For this reason, shortly before 1880, the history of the shutter begins , because the high sensitivity of the plates required the design of mechanisms capable of letting light enter the camera for only a hundredth and even a thousandth of a second. The intensity of the light had to be precisely evaluated and thus the photometer became a true measuring instrument.
George Eastman, 1854-1932
Georges Eastman
The American Georges Eastman, founder of Kodak, conceived in 1888, the idea of a soft support. The glass plates will be progressively replaced by the celluloid rolls.
Color reproduction
Still lacking photography, the reproduction of colors. The first attempts were the initiative of Edmond Becquerel in 1848, then that of Niépce de Saint Victor, in 1851, who demonstrated that a silver plate covered with pure silver chloride directly reproduced colors, although in an unstable way.
In 1869, Louis Ducos du Hauron achieved, in Agen, the first color photography applying Maxwell’s demonstrated principle of the decomposition of light through the three fundamental colors, red, yellow and blue. The latter took three photographs of the same subject, through a respectively red, blue and yellow filter. From these, he obtained three positives of the same color from each of the filters used. By exactly superimposing the three images, he obtained the restitution of the colors.
Self-portrait of Gabriel Lippmann
The physicist Gabriel Lippman received the Nobel Prize in 1906, for having discovered in 1891, the means of obtaining color photographs directly on the same plate, by means of an interferential procedure that was already foreshadowed by holography. Too complex, this invention did not transcend the laboratory stage.
The first color mono-plate procedure that could be used by amateurs was born in 1906. The autochrome invented by the Lumière brothers took up the principle of trichromy synthesis achieved this time on a single plate by adding a mosaic of three-filter micro-filters. colors made thanks to potato starch grains.
- Fisher’s discovery of the chromogenic developer from 1911 gave color photography a new direction. Some developers had been observed to produce images with a dominant color rather than neutral black and white.
Brothers Auguste Lumière (1862-1954) and Louis Lumière (1864-1948).
The tri-chromium principle was taken up by the Agfa Company to develop, in 1936, the Agfacolor films, made up of three superimposed layers sensitive respectively to blue, green and red. A developer was developed that colored the layers according to the color of their sensitivity. Thus, the possibility of reproducing the colors produced improvements in the optics, to faithfully transmit the colors of the object in the film.
In 1935 two Americans L. Mannès and L. Godowsky improved the procedure. Purchased by Kodak, it took the name Kodachrome. Although our current color films are very sophisticated, it does not prevent them from always having to resort to silver bromide, gelatin as well as the basic principle of Agfacolor and Kodachrome.
