People had been able to project and fiddle with light and shadow for centuries, but they never really figured out how to "fix" an image to something and make it stick. This is where nice Nicephore comes in. He figured out how to get an image to stick. But he didn't fix the image to paper. Instead, in 1826, he managed to get the image to stick to a polished pewter plate.

Nicephore's forays into photographic fabulousness didn't begin in 1826, of course. This stuff takes time. He actually started tinkering with the problem back in 1816. He first took transparent engravings and placed them on glass plates coated with varnish. Trying to get photos to stick would initially be a sticky proposition.

Experimenting with different materials
Nicephore worked quite hard to make his plan come together. In his earliest experiments, he coated paper with silver salts (which blackened with daylight). He placed this paper at the back of a camera obscura and in May of 1816, got his first image. This one was a negative and didn't last. Once daylight hit the paper, the entire sheet became completely black.

Wanting to create positive images, true renderings of what his eye could see, Nicephore tried using different substances that reacted to light by bleaching, rather than darkening the paper. He tinkered with salts, iron oxide, and manganese black oxide. He did make some progress, but he kept running up against the issue of how to get rid of the chemicals that weren't light-reactive.

Nicephore figured that acid was a nasty enough substance that it ought to do something. So he tried to use acid to etch images. His theory was that he could spread acid on calcareous (chalky) stone and that the acid's strength would vary according to the intensity of the light, thereby etching the image into the stone.

Minor detail: acids don't decompose with light, so this whole set of experiments was a bust. Nicephore got fed up and took the year 1817 off.

Screwing around with this stuff, though, led to an interesting observation. Nicephore figured out that he didn't need to restrict his research to substances whose photochemical transformations were visible to the human eye. It was possible, he observed, that an invisible change in chemical properties under light might cause an image to appear during a reaction.

Judea bitumen
By 1818, he managed to get an image to stick for a full three months, before fading away into history. That's an image we'll never see. In 1822, he managed to create the world's first photocopy (actually, what photographers call a "contact print") by placing a drawing of Pope Pius VII on a glass plate coated with Judea bitumen, a nasty organic tar-like substance used to waterproof boats and create flamable cities.

It's believed that the ancient North African city of Carthage used bitumen as a primary building material and once the Roman general Publius Cornelius Scipio Aemilianus Africanus the Younger conquered and set fire to Carthage in 147 B.C., the whole city burned to a crisp faster than you could say "Catherine O'Leary's cow".