1. An Introduction to Photography: Basic Concepts & History

December 19, 2022

1. An Introduction to Photography: Basic Concepts & History

How a Camera Works

Photography is made possible by two important scientific fields, physics and chemistry working together. First, in physics, photography makes use of the “camera obscura” a discovery dating back to the philosophers Mozi (c. 470-391 BC) in China, and Aristotle (c. 384-322 BC) in Greece (working independently, obviously). This is a box, or room, from which light can only enter via one tiny hole. The result is that all light passing through the hole creates an upside-down mirror image on the opposing wall – a mirror of everything happening outside the hole, in real time:

You can set up your own camera obscura using any room with a window – it really works!

Fun Fact: Your eyes are also camera obscuras! They work in the same way, with the iris acting as the shutter to allow light into the retina, where images are observed (the optical nerve flips the image back so that it’s right-side-up):

The second important scientific discovery was that of light-sensitive chemistry, developed in several different ways at around the same time, starting in the 19^th century. The first was the French inventor Joseph Nicéphore Niépce who, in 1822 used Bitumen of Judea, which would harden wherever light hit it, forming a permanent image. One had only to wash away the bitumen that hadn’t hardened, using a lavender solvent, to get the final image. Unfortunately, the exposure time took 8 hours so it wasn’t practical.

View from Window at Le Gras, by Joseph Niepce, 1826

Louis Daguerre, who worked with Niépce, developed his own process in 1837, using iodine and bromine fumes on a silver plated copper sheet, to make it light sensitive. The plate was then exposed using a camera obscura, developed using fumes of mercury, and then fixed in a bath of hot salt water. The process, besides being highly toxic, took a great deal of time as well, up to 45 minutes for a photo (adding the bromine fumes greatly reduced exposure time to around 30 seconds). It made only one small copy, which was a mirror image of reality (flipped). Nevertheless, this was the first commercially successful form of photography, commonly used for family portraits. Daguerreotypes became popular all over the world – in part because Daguerre never patented his process or device, so anyone could make their own freely.

A selection of Daguerreotypes

Meanwhile in England, from 1834 - 41, the inventor William Fox Talbot created a different, superior process, making a translucent negative which could be used to print unlimited large copies of an image on paper, sensitized with silver chloride. And the exposure time was a split second, allowing the photographer to capture all sorts of subjects in motion. Talbot kept his work secret until reading about Daguerre, and then feared his method would be ignored.

Funny enough, Talbot’s process wasn’t popular at first, because of the patent he held until 1853 - no one could use his process without his permission and paying him a fee. After Talbot let his patent expire, his negative-positive process eventually replaced Daguerreotypes, becoming the dominant photographic process all over the world - still used today, although it's now being replaced by digital photography.

There were other chemists who improved Talbot’s process. Frederick Scott Archer developed a wet collodian plate process in 1851. This was improved with the dry gelatin process around 1870. James Maxwell created the first color photograph in 1855:

It was actually a composite of three monochrome photos, with filters for green, red, and blue. These photos were then printed one after the other on the same piece of paper. Hermann Vogell found ways to improve the sensitivity of the paper to different colors, such as red and yellow, to improve the colors in the final image. All these methods involved using a glass plate for the negative. George Eastman created the first flexible film roll in 1885, although it was highly flammable. Kodak introduced the safer cellulose acetate film in 1908. The Lumiere brothers in France developed the first practical, and commercially successful color photo process, called Autochrome in 1907. This was further improved by the Kodachrome process in 1935 which was a 3-layer film roll, each layer sensitive to different colors. In 1963, Polaroid developed a process of instant color film which required no processing:

The Polaroid Model 95

These were the ways people took photos up until digitization in the 1980’s, and many fine-art photographers continue to use roll film, and some still make Daguerreotypes. And it’s worth noting noting, digital cameras copy, as much as possible, the concepts, terms, and principles of traditional photography.

Inside a Digital Camera

So, what makes a hand-held camera different from a camera obscura? There are different kinds of cameras (see lesson here), but basically, most of them have more gadgets inside. Here’s how it works:

As you can see, your camera is like a little house of mirrors, with light bouncing around from one mirror to the next like a rollercoaster, passing through the viewfinder to your eye. When you press the shutter button, the shutter opens, and the sensor plate is exposed, recording an image. With traditional roll-film cameras, instead of a sensor plate, the film itself would be exposed (one little square of it).

Some Leading Figures in Early Photography:

Joseph Nicéphore Niépce (French, 1765-1833)

Louis Daguerre (French, 1787-1851)

Anna Atkins (English, 1799-1871)

William Fox Talbot (English, 1800-1877)

David Hill (Scottish, 1802-1870)

Alexander Gardner (Scottish-American, 1821-1882)

Auguste-Rosalie Bisson (French, 1826-1900)

Carleton Watkins (American, 1829-1916)

Henry Peach Robinson (English, 1830-1901)

Eadweard Muybridge (English, 1830-1904)

Felice Beato (British-Italian, 1832-1909)

Antonio Beato (British-Italian, 1835-1906)

Timothy O'Sullivan (American, 1840-1882)

John Karl Hillers (American, 1843-1925)

Some of the Greatest Artworks of Early Photography:

Boulevard du Temple, by Louis Daguerre, 1838

NOTE: the above image was actually of a very busy street. So, where did all the people go? You can't see them because this photo required a 45 minute exposure, and the pedestrians didn't stand in one place long enough for the camera to register them - except for one man having his shoes shined. He and the shoe-shine boy are the only two people visible in the scene.