Photography was the product of an evolution, not a single discovery. By the early 1800s, lenses and the darkening effect of sunlight on silver nitrate were widely known. For centuries, people with drawing skills had been using viewing devices like the camera obscura to copy nature precisely. During the late 1700s a growing middle class with a taste for realism created a new demand for pictures of the world around them. The desire remained to make light itself "fix," or make permanent, the image in the camera. This challenge inspired artists and scientists working independently in different countries to enter the "race" for invention.

Six men were aware of and in some instances spurred on each other's work. They stand out for their contributions to the invention of photography.