The worlds first photograph - 1826

This is the world's oldest photograph. 

One summer day in France in 1826, Joseph Nièpce took the world's first photograph. It's a photo of some farm buildings and the sky. It took an exposure time of 8 hours.

No one's exactly sure how he did this or what chemicals were used. All that's known for sure is that the photo is on an 8"x 6.5" pewter plate. 

Nièpce took the photograph from the upper-storey of his estate Le Gras in the village of St.-Loup-des-Varennes in Burgundy. Though indistinct, it is possible to make out the panes of Nièpce's workroom windows to the left and right of the picture. Through the window one can see a courtyard and the rooftops of various buildings on the property: the upper loft of the granary, the slanting roof of the barn and, on the right, another wing of the family house. In the distance and to the left is a pear tree and on the right and almost in-line with the horizon is the roof and chimney of the bakery.

The current theory about how the photograph was taken is that Niepce coated the pewter plate with bitumen, a petroleum derivative sensitive to light. After it spent those 8 hours hardening, he washed the plate with a mixture of oil of lavender and white petroleum. This dissolved the portions of the bitumen that didn't 'see' direct light, so didn't harden. Niepce called his work a "heliograph," in a tribute to the power of the sun.

“I have the satisfaction of being able to tell you that through an improvement in my process I have succeeded in obtaining a picture which is as good as I could wish.... It was taken from your room at Le Gras with my biggest camera and my largest stone. The objects appear with astonishing sharpness and exactitude down to the smallest details and finest gradations. As the image is almost colorless, one can judge it only by holding the stone at an angle, and I can tell you the effect is downright magical.” 

-- Joseph Nicéphore Nièpce’s letter to his brother, Claude, describing the results of his first successful experiment in 1824.