Photography is an art that took many years, and the efforts of many individuals to perfect. Many different people in many different fields contributed to this "light writing." Chemists, artists, inventors, and engineers all lending a crafting hand to the art. Photography was eerily predicted in the mid-1700's by la Roche in his work Giphantie. In this tale, it was possible to record images from nature on a canvas coated with a sticky substance. Unfortunately the author died before he could see his fiction become real.
Two different scientific process had to combine in the 1830s to make photography possible. Its surprising that photography did not come around sooner due to the fact that the two processes were around for a long time before they were put together to from photography. The first process was optical. The camera obscura was the first know camera. The principle was know to the Arabic's before 1038 and had been drawn by Leonardo de Vinci in 1519. The camera obscura was a dark chamber or room in which there was a small hole in the wall. The picture would be formed on the opposite wall, however, it would not be sharp due to the lack on a lens. Giovanni Pattusta della Porta was the first to suggest the camera as a guide for drawing in 1558. As the interest in the camera obscura grew its size diminished, until it became a portable device. The artist could just put a piece of tracing paper on top of the viewing screen and trace the picture. Hence, the camera became on of the artists tools.
The second process was chemical. For hundreds of years chemists knew that some colors are bleached in the sun but had made no distinction between heat, air, and light. In the seventeenth century, Robert Boyle had reported that silver chloride turned dark after exposure, but believed this was due to air and not light. Angelo Sela, around the same time period, noticed that powdered nitrate of silver is blackened by the sun.