Introduction to the History of Photography

The concept of the photographic latent image is characterized by B. Newhall as: " a relatively week light signal is amplified enormously by development" (1) The action of light in the sensitized plate, paper or film is just the initial stage towards the formation of the photographic image, a process that must be complemented by development. The concept, according to Newhall, was announced by Talbot in 1841. Previously, Talbot allowed the action of light to be prolonged until the image appeared. The new procedure greatly reduced the necessary exposure time. The idea that a feeble image can be "increased, brought out, and strengthened" after the completion of the exposure process, was part of the daguerreotype process, as Talbot himself noted in an address to the British Association for the Advancement of Science, after Daguerre´s disclosure of his invention. (2) It was in fact the pioneer discovery of Niépce in the 1820s. (3) The pictures from the Salomon Andree ...