Early Photographic Process and Images

(Answer the REVIEW QUESTIONS as you read this.)

Early Development of the Optics for “Cameras”

Some of the optical parts of a camera were in use long ago – Aristotle discussed the pinhole principle, and Arab scholars refined it around 1000 A.D. The camera obscura was in use as a drawing aid since Leonardo da Vinci's time. It was a box with a pinhole in front. Light rays coverged through the pinhole and created a reversed image at t5he back of the box, which an artist could trace. The astronomer Kepler added a lens to improve the quality in the 1600's, and camera obscuras as large as a small theatre were popular with audiences, who would pay to sit inside the box and see the world outside projected through the pinhole lens onto the back wall. (Ya, this was WAY before TV!)

However, the feat of capturing an image permanently required much experimentation with photo -sensitive (light-sensitive) chemicals, and was not accomplished until the beginning of the 19^th century.

Trying to Capture Light: Messing Around with Photo-Sensitive Chemicals

Thomas Wedgewood, the famous china manufacturer, created images on china around 1800. He was also a chemist, and coated china with silver salts which he knew would blacken on exposure to light, and then placed a pattern of leaves on top of the china. Exposing this to light darkened the silver salts except where the leaves blocked it, so Wedgewood had created the first photographic image (a photogram, which we will create too!). The problem was that the salts continued to blacken when the leaves were removed, so the images soon turned completely black.

The first known permanent photographic image was created by Joseph Niepce in 1825. He coated an engraved drawing with oil to let light shine through it. He then placed this on top of a metal plate coated with bitumen (a form of asphalt). Shining light through the engraving for several hours hardened the parts of the bitumen that were exposed to more light. Washing off the softer bitumen left the image of the engraving where the bitumen had hardened, and he used this to make prints, which he called "heliographs". Here's the first permanent photographic image, created in 1825 from an 18^th century engraving of a man leading a horse. Notice that it started with an engraving, not a live image from a camera.:

Combining Photo-Chemistry with a Camera

In 1827, Niepce mounted one of his bitumen plates in a camera obscura, and faced the device out the window of his estate in France for 8 hours. The result was grainy but recognizable, and stands as the first permanent photograph using a camera. This is HUGE, because it’s really the birth of camera-based photography.

Commercial Photography Is Born

Niepce formed a partnership with Louis Daguerre in 1829. Daguerre experimented with different photo-sensitive materials mounted in his camera obscura, and in 1835 discovered that silver iodide was very sensitive to light, and an image formed on a silver iodide coated copper plate could be made visible using mercury vapours as a developer. He still had Wedgewood's problem: the image would keep darkening and soon be unrecognizable. He solved it in 1837 by washing away unexposed silver salts with a solution of table salt (precursor of the fixer we'll use in our darkroom). He patented this process as the Daguerreotype, and soon Daguerreotype studios sprang up all over an excited world, launching commercial photography! Here's one of the most famous photos ever, a Daguerreotype of a street scene in Paris (Boulevard du Temple) in 1838:

Because the exposure lasted ten minutes, anything that moved, like horse and pedestrian traffic, wasn’t there long enough to be captured, but a man patiently standing still to have his boots shone became the first person captured photographically. Can you spot him?

Below is another Daguerreotype, the first self-portrait, by Robert Cornelius in 1839:

The Competition (It Pays to be First)

In England, William Henry Fox Talbot was working on another process, the Calotype, when news of the Daguerreotype reached him. This process used silver chloride coated on paper as the photo-sensitive material, placed in a camera. The resulting negative image was then placed on top of another sheet of coated paper, and light shone through it resulting in a clear positive image. This was to be the basis for the negative-positive process used from then on for most photography. Here's his first negative and his notes from 1835, along with a positive print from the negative:

By the 1840's, Talbot's calotypes had excellent quality. Here's "The Ladder" from 1844:

Sadly for Talbot, even though his process gave better results, the Daguerreotype got established first, and Talbot wasn’t as successful commercially.