Johann Heinrich Schulze

1687-1744

German physician and anatomy professor who made a significant discovery in the development of photography when he observed that silver salts darkened when exposed to sunlight.

In 1725, while attempting to create a phosphorescent material by combining chalk with nitric acid containing dissolved silver, Schulze noticed that sunlight turned the substance black. He tested words and shapes cut out of paper and placed against a bottle of the solution, but he never made a permanent image.