The Calotype process, invented by W.H. Fox Talbot in 1839, is one of the earliest photographic processes. In this method, paper is coated with silver iodide and treated with a solution of silver nitrate and gallic acid. After exposure to light, the paper is developed in a silver nitrate solution, producing a negative image that can be used to create multiple positive prints. The Calotype was revolutionary because it allowed for reproducible images, unlike the one-off daguerreotypes, and laid the foundation for modern negative-to-positive photographic printing.