history of photography In 1614, Angelo Sala used silver nitrate that was burned by sunlight wrapped in paper. This he stated in his writing entitled Septem Planetarum terrestrium Spagirica recensio, "If silver nitrate powder is exposed to sunlight, it will turn black like ink." This discovery with the effects of sunlight was considered less useful by other scientists. In 1717, Johann Heinrich Schulze, a German professor, accidentally used a vial containing silver nitrate and chalk near a window. This mixture makes it dark with some white and makes lines on the bottle. A chemist, Carl Wilhelm Scheele discovered ammonia dissolved in silver nitrate but not dark particles. This discovery made it possible to stabilize an image of silver nitrate, it is considered an experimental discovery of photography. Not long after, in 1800, Thomas Wedgwood captured images with a camera obscurator. Unfortunately Wedgwood died at the age of 34 in 1805. "Boulevard du Temple", a dague