History of photography

Photography is a method for producing lasting images by means of a chemical reaction that occurs when light hits a specially prepared surface. It was invented during the first three decades of the 19th century as a direct consequence of advances in chemistry and optics (the science of the behavior of light). The word photography comes from two Greek words that mean “writing with light.”

Although the technology is fairly recent, the origins of photography lie in an artistic technique known as single-point or linear perspective, which was developed in the early 1400s. Pioneered in Italy by architect Filippo Brunelleschi and others, the system of single-point perspective provided painters with a method for depicting three-dimensional space on a flat surface. It is based on the notion of a single observation point and results in lines that appear to recede into the distance by converging on a fixed point on the horizon, called the vanishing point.

In the 16th century many artists employed a boxlike device known as a camera obscura (Latin meaning “dark room”) as an aid to depicting space with single-point perspective. This consisted of a box with a pinhole on one side and a glass screen on the other. Light coming through this pinhole projected an image onto the glass screen, where the artist could easily trace it by hand. Artists soon discovered that they could obtain an even sharper image by using a small lens in place of the pinhole. The camera obscura was used by Renaissance artists such as Michelangelo and Leonardo da Vinci.

Also essential to the invention of photography was knowledge of the light sensitivity of certain materials. More than 2000 years before the invention of the camera obscura, the ancient Phoenicians knew that a certain snail, the purpura, left a yellow slime in its wake that turned purple in sunlight. In the 18th century a German anatomy professor, Johann Heinrich Schulze, observed that silver salts darkened when exposed to light. But the idea of making pictures using this phenomenon did not occur to him. That innovation required the talents of a later generation of scientists.

By 1800 a young English chemist, Thomas Wedgwood, had succeeded in producing images of leaves on leather that he had treated with silver salts. However, he could find no way to halt the darkening action of light and his leaf images eventually faded into blackness. His attempts to capture the image displayed by a camera obscura also proved unsuccessful. For the birth of photography two key discoveries were still needed: a way to combine a light-sensitive material with the camera obscura, and a way to fix, or make permanent, the resulting image.

In the 1820s French scientist Joseph Nicéphore Niépce was experimenting with improvements to the new printmaking technique of lithography. In the process he discovered a way to copy engravings onto glass and pewter plates using bitumen, a form of asphalt that changes when exposed to light. He first coated a drawing or etching with oil so that light would shine through it more easily, then placed it on a bitumen-coated plate and exposed the plate to light. Light shining through the paper burned an image into the dark bitumen, creating a nearly perfect copy of the original. Niépce could then etch and print this image using traditional printmaking techniques. In 1826 he put a bitumen-coated plate in a camera obscura, which he then placed with its lens facing the window of his estate in central France for eight hours. The resulting image, View from the Window at Le Gras (Gernsheim Collection, University of Texas at Austin), is the earliest camera photograph still in existence.

In 1826 Niépce began sharing his findings with Louis Jacques Mandé Daguerre, an artist and theatrical designer who owned a theater in Paris. This theater, the Diorama, provided a popular spectacle consisting of large, painted scenes that were shown in succession, changing before the viewers’ eyes. Like Niépce, Daguerre hoped to find a way to create images from the camera obscura, but he had little luck until the two decided to become partners in 1829. Even then, Daguerre’s most important discovery came only in 1835, two years after Niépce’s death. Daguerre found that the chemical compound silver iodide was much more sensitive to light than Niépce’s bitumen, and he placed a copper plate coated with silver iodide in a camera obscura. After exposing this plate to light for a relatively short time and then to fumes of mercury, an image appeared. One problem remained: The image darkened over time. But in 1837 Daguerre solved this final obstacle by washing away remaining silver iodide with a solution of warm water and table salt.

	First Negative Image British amateur scientist William Henry Fox Talbot invented an early method of photography in 1835. Talbot’s method, which he called “photogenic drawing,” involved coating a sheet of paper with light-sensitive chemicals and exposing it to light through a simple pinhole camera. This produced a paper negative, which he then used to create a positive image. Talbot had difficulty at first in preventing the paper from continuing to darken when exposed to light. As a result his method was not initially successful. However, it was later refined into the calotype process, and became the basis for most modern negative-to-positive photography. Encarta Encyclopedia William Henry Fox Talbot/Stringer/Getty Images
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On January 7, 1839, Daguerre’s process, called the daguerreotype, was announced to the French Academy of Sciences, and hence to the world. The announcement by respected French scientist François Arago was brief but nonetheless created a sensation. Newspaper accounts spoke of pictures 'given with a truth which nature alone can give to her works.' Half a year later the French government gave Daguerre and Niépce’s son, Isidore, lifetime pensions in exchange for their release of all rights to the invention and public disclosure of the process. The daguerreotype was to become France’s gift to the world.

Just three weeks after Arago’s announcement in Paris, William Henry Fox Talbot, an English amateur scientist, read a translated account of the discovery. Perturbed, if not distraught, Talbot recognized Daguerre’s invention as similar to his own unpublicized process, which he called photogenic drawing. Talbot moved quickly to claim priority over Daguerre, writing to members of the French Academy and presenting his process in a paper to the Royal Society in London, England.

	Daguerreotype of Daguerre In 1839 French inventor Louis Jacques Daguerre announced his development of the first photographic process suitable for widespread use. Called the daguerreotype, Daguerre’s process involved recording an image on a metal plate coated with special chemicals. Daguerre is shown here in a daguerreotype from 1846. Encarta Encyclopedia Corbis
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To create a photogenic drawing, Talbot first coated a sheet of drawing paper with the chemical compound silver chloride and, placing it inside a camera obscura, produced an image of the scene with the tones reversed (a negative). He then placed the negative against another coated sheet of paper to produce a positive image. Talbot did not find a way to make the image permanent until a month after Daguerre’s announcement. But his photogenic drawing process—later refined and renamed the calotype—forms the basis for most modern film technology, which relies on negatives to produce multiple positive prints.

For a number of reasons, including the imperfections of Talbot’s process, the daguerreotype was the method of photography that first took the world by storm. The low-cost daguerreotype became so popular that, by the end of 1839, Paris newspapers were referring to a new disease called Daguerreotypomania. With improvements in its sensitivity to light, the daguerreotype quickly proved ideal for portraiture. By 1840 daguerreotype studios throughout Europe and in the United States were producing unique, detailed likenesses that were set inside hinged leather cases. An emerging middle class gazed in amazement at its own image in these 'mirrors with a memory.'

Photography  arrived in the United States due to the enthusiasm of Samuel F. B. Morse, an American artist and inventor. Morse visited Daguerre in Paris in March 1839 and observed a demonstration of the daguerreotype process. Morse returned to the United States to spread the news, and by year’s end new practitioners such as John Plumbe of New York City and the Langenheim brothers (William and Frederick) of Philadelphia had mastered the daguerreotype process and set up successful portrait studios. The yen for daguerreotypes persisted in America well into the 1850s, long after European photographers had switched to a much improved positive/negative process derived from Talbot’s method. Most pictures of the California Gold Rush of 1849, for example, are daguerreotypes.