Camera Obscura: Ancestor of Modern Photography

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Camera Obscura: Ancestor of Modern Photography

Overview

Capturing an image from life was long ago the sole proprietorship of the skilled artist, whose brushstrokes precisely recreated portraits of man and landscape on canvas. That art is now shared by anyone who cares to peer through a camera's viewfinder and snap the shutter. Modern photography had its start in the 1800s, with the invention of the Dageurrotype and Englishman W. H. Talbot's (1800-1877) negative-positive development process. But its roots can be traced to centuries earlier, to a simple mechanism—a dark room, in which light passed through a pinhole, projecting an image on the opposite wall. It was called camera obscura.

Background

More than 2,000 years before the invention of the camera obscura, its earliest predecessor came to light in ancient Greece. In 500 b.c., the philosopher Aristotle (384-322 b.c.) discovered that by passing sunlight through a pinhole, he could create a reversed image of the Sun on the ground. He used this device as a means for viewing an eclipse without having to stare directly into the Sun.

Aristotle's experiments went no further. He could not explain why the image was created, or why it was in reverse. In 1035 an Egyptian scientist named Ibn al-Haitham (965-1039) continued Aristotle's work, by first devoting himself to the understanding of what makes up light. He had a theory that light traveled in straight lines, called rays, and set out to prove his theory by arranging a line of candles on a table, lighting them, then standing behind a screen that separated him from the candles' light.

Al-Haitham pricked a hole in the screen and watched as the light rays passed through it. The image from a candle placed at the left side of the hole would pass through and strike the wall to its right, and vice versa. Light from the top of the candle flame would strike downward of the hole. Thus, he proved that light rays move in straight lines. He recorded his findings in a book titled Kitab al-Manazir. Centuries later, the book found its way to Europe.

In Italy, inventor and artist Leonardo da Vinci (1452-1519) caught word of al-Haitham's work and decided to try his own experimentation using mirrors, lenses, and pinholes. In around 1510 he wrote in his notebooks:

When the images of illuminated objects pass through a small round hole into a very dark room...you will see on the paper all those objects in their natural shapes and colors. They will be reduced in size, and upside down, owing to the intersection of the rays at the aperture.

In Italian, the name for darkened room, camera obscura, became synonymous with the projection of light through a small hole. In 1521 one of da Vinci's students, Cesare Cesariano (fl. 1520s), published the first description of the camera obscura, but it was not widely read. The public did not gain knowledge of this new device until an account was written more than 30 years later by Italian nobleman Giovanni Battista della Porta (1535-1615). He described the process for assembling the camera obscura in his book Magiae Naturalis (Natural magic, 1558):

You must shut all the Chamber windows, and it will do well to shut up all holes besides, lest any light breaking in should spoil all. Only make one hole...as great as your little finger....

When the Sun shone through the hole, an image would appear "and what is right will be the left, and all things changed."

Impact

Della Porta was the first to be able to manipulate the image, through the use of a camera obscura fitted with convex lenses and mirrors. A concave mirror would enable the device to reflect an image right side up. He suggested that artists could project scenes from nature on a piece of paper to assist in the rendering of their works.

Thrilled by his new invention, della Porta summoned his friends and important members of Naples society to his home for a demonstration. Instead of sharing his excitement, the group was appalled when they saw real human images displayed on the wall, believing it to be the work of witchcraft. The Catholic Church got wind of della Porta's demonstration and promptly charged him with sorcery. His work was banned for six years.

This did not usher in the end for the camera obscura, however. The Magiae Naturalis was disseminated throughout Europe, and the device became a novelty item across the continent. Meanwhile, an interest in optics exploded throughout the European scientific community. In 1604 German astronomer Johannes Kepler (1571-1630) studied the mathematical laws governing mirror reflection, and seven years later worked out the theory of lenses. Scientists were unknowingly providing an invaluable service to the artistic community.

Throughout the next century, several improvements were made to the camera obscura. A German mathematics professor, Daniel Schwenter, discovered that by drilling a hole through a wooden ball and placing a lens at either end, he could focus images in any direction upon a wall. Scientist Friedrich Risner (d. 1580) invented a portable version of the camera, housed in a collapsible tent. The only problem was, the operator still had to climb inside the clunky device.

Johann Zahn (fl. 1680s), a German monk, solved that dilemma by inventing a camera obscura that was just 9 inches (22.86 cm) high and 24 inches (61 cm) long. Inside the box was a mirror placed at a 45-degree angle to the lens. The mirror reflected the image to the top of the box, where he had placed a sheet of frosted glass. The glass was covered with tracing paper, allowing images to be easily copied by an artist. Zahn's design would remain in use for nearly 200 years.

Further assisting the artist was the invention of the camera lucida by William Hyde Wollaston (1766-1828) in 1806. This was no actual camera, but rather a glass prism suspended at eye level from a brass rod. This device enabled even the most untrained artist to trace an image on a piece of paper, by allowing him to view his subject and the paper at the same time. But even the camera lucida required the skilled hand of an artist, and many more people clamored for the chance to capture reality.

The camera obscura had made it possible to successfully project an image—the next challenge was to make that image permanent. The first attempts at freezing an image were made by Tom Wedgwood (son of the famous pottery maker Josiah Wedgwood) in 1800. Drawing on his understanding of the camera obscura, as well as the discovery by German natural philosopher Johann Heinrich Schulze (1687-1744) that silver salts are light sensitive, he began experimenting by coating paper with silver nitrate, then placing it in a camera obscura and exposing it to the Sun's rays. His experiments were unsuccessful—the image refused to hold on the paper. Wedgwood abandoned his work due to poor health.

In the early 1800s French printer Joseph Niepce (1765-1833) achieved a greater degree of success. He was convinced that if he could coat a surface with light-sensitive chemicals, he could recreate an image by exposing that surface to the Sun. Niepce placed an engraving between a plate coated with a substance called bitumen of Judaea, and a sheet of clear glass. The resulting images of the engravings he called heliographs.

In 1824 Niepce switched from copper and zinc plates to a pewter plate, which he coated with a special light-sensitive varnish and placed into a camera obscura. He set the camera in the window of his home and opened the aperture. He left it in the Sun for a full eight hours.

When Niepce returned, he removed the pewter plate and dipped it into a chemical bath. The softest portions of the varnish softened, while the hardest sections remained. While indistinct, the image revealed was unmistakably the view out of his window in Saint-Loup-de-Varennes. He could see the outlines of buildings, roofs, and chimneys. It was the world's first permanent photograph.

In 1829 French scene artist Louis Jacques Mandé Daguerre (1787-1851) formed a partnership with Niepce, believing that he could improve upon the latter's heliographic process even further. Daguerre discovered that he could create an image on plates coated with silver iodide, which could then be "developed," that is, permanently affixed to the plates, with the use of sodium chloride (salt). Exposure time quickly dropped from eight hours to a mere (at the time) 30 minutes. His photographic process, which he called "daguerreotype," proved the next major step in the evolution of modern photography.

The final piece of the puzzle that launched modern photography was discovered by Englishman William Henry Fox Talbot. In 1834 Talbot invented the first light-sensitive paper by soaking it in a salt solution, then coating it with silver nitrate. A year later, he wrote: "In the Photogenic...process, if the paper is transparent, the first drawing may serve as an object to produce a second drawing, in which the lights and shadows would be reversed."

The image that Talbot captured was a "negative"—that is, the light objects appeared dark on the paper, and vice versa. He realized that by placing this negative on top of a second sheet of paper and exposing both to sunlight, the process would repeat itself, forming a "positive," or true image.

By the mid-1800s photography became the rage throughout the world. People everywhere were thrilled at the sight of their own visage, preserved forever on Daguerre's patented plates, and later on film. From purely artistic application, photography spread into the news arena, capturing scenes of horrific violence during the American Civil War through the lens of Matthew Brady (c. 1823-1896).

From a simple projection of light through a pinhole eventually emerged an entire industry. The expression "a picture is worth a thousand words" has proven true, with photographs capturing our emotions, encouraging us to purchase a wide array of products, and showing us a world that mere words could never reveal.

STEPHANIE WATSON