Engines of Our Ingenuity

No. 124:
CAMERA OBSCURA

by John H. Lienhard

Click here for audio of Episode 124.

Today, let me take your picture with a home-made camera. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The Latin word for a large vaulted room is a camera. We get the word chamber from it. A comrade is literally someone who sits in the same room with you. The thing we take pictures with is also called a camera, and that comes from an ancient device called a camera obscura -- literally a dark room. Here's how it works:

You create a large room with only one light source -- a tiny hole through one wall. That hole projects an accurate image of the outside view on to the opposite wall. Without film, you can't really "take a picture" with it, but you can trace the image with a pencil, if you want. Aristotle was familiar with the idea, and medieval writers had a lot to say about it.

When I was young, photographic film was pretty slow, and it came in large sizes. We used the camera obscura idea to make something called a pinhole camera. We'd punch a pinhole in one end of a shoebox and mount film in the opposite end, with everything sealed up tightly. Then we'd point the box at a subject, uncover the pinhole -- just for a moment -- and we'd get a passable photograph.

Of course no one put film in a camera obscura until the 19th century, but they were made with lenses as early as the 16th century. The name camera obscura was given by the astronomer Johann Kepler, who used a fairly complicated lens system to make solar observations with one in 1600. In the 17th century the camera obscura was highly refined as an aid to artists, and that's the period when we began to see remarkable improvements in the way painters handled perspective.

The interesting thing about all this is that photography didn't have to fight for acceptance as many inventions do. The camera itself had been highly sophisticated for 200 years, and it just had to wait for someone to invent a way of recording the picture automatically. And that in turn had to wait for eighteenth-century improvements in chemistry.

The French lithographer Joseph Niepce finally made the first photograph. It was an eight-hour exposure of the view from his window, made in 1826. The image was formed out of hardened bitumen on a pewter photographic plate. It took him ten years of experimentation to get there, but what he did was to come up with the long-awaited solution to a long-standing puzzle. After 2000 years, he finally provided film for the camera obscura.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Newhall, B, The History of Photography. New York, The Museum of Modern Art, 1964. This episode has been greatly rewritten as Episode 1772.

The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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