One summer day in France in 1826, Joseph Niepce 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. Voila! It must have felt pretty incredible to see the photo back then.
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. It’s so faint it has to be tilted in order for the light to catch it just right, to see it at all. The Getty Museum in California did two weeks
of tests in 2003 in a joint project involving the Rochester Institute
of Technology and France’s Centre de Recherches sur la Conservation des
Documents Graphiques. Then it
went back on display at the University of Texas,
where it’s been on display since 1964. I’m not sure why it’s in America not France, but "hah".
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. Pretty damn clever.
Niepce called his work a "heliograph," in a tribute to the power
of the sun.
Source: anomalies-unlimited.com