Following the progress of technology can be pretty interesting. The camera obscura we looked at yesterday played a huge role in the development of the first camera photography. Up until the 1820s, the camera obscura would allow artists to project and image and paint it. However, our modern idea of photography is a photochemical process. That process did come along until Nicéphore Niépce created the first photograph in 1822 when he used a camera obscura to project an image on a plate with bitumen. The bitumen would harden as it was exposed to light and then the soft bitumen could be washed away. Exposure times were measured in hours and possibly days.
So, Niépce contacted artist and physicist Louis Daguerre for help in finding a better process. While Niépce had been on the right track method-wise, Daguerre and he realized that there were better chemicals to use for creating a photographic image. Heinrich Schultz had found in 1816 that a mixture of silver and chalk would darken when exposed to light. Niépce and Daguerre began pursuing the silver angle. In 1833, Niépce died leaving Daguerre to carry on the work. In 1837 he created the daguerreotype which used a silver film on a plate that had been fumed with iodine vapor. The silver iodine would react with light in a relatively short amount of time (now measured in minutes). He also found that using mercury fumes would “fix” the image and stop the development process. It was this process that he used for his Boulevard du Temple photograph from 1838 that you see above.
In 1839, Daguerre announced his process to the French Academy of Sciences, but would only show his photographs to a select few people and kept the process a closely guarded secret. However, later that same year, the French government gave him and Niépce’s family a pension in exchange for making the photographic process public knowledge. The French government wanted the ability to collect images to be a gift of France to the entire world.
Interestingly, Hercules Florence had created a similar process in 1832 in Brazil. However, living in the newly independent Brazil did not afford him the same scientific recognition as a couple guys playing with mercury vapors in France. English inventor William Fox Talbot claims he had developed a similar process in 1835 but had kept it a secret. When the daguerreotype was released to the world, he began working on his process again and improved it. He would use a sodium thiosulfate mixture to dissolve the silver salts and fix the image. In 1840 he developed the calotype process which was very similar to the daguerreotype process, but would create a negative image. This would allow the photograph to be copied many times via contact printing methods.
Talbot patented the calotype process and spent the rest of his life in lawsuits defending his patent.
[Image Credit: Public Domain]