Johann Heinrich Schulze (1687-1744)'s experiments laid the foundations on which photography is based. Schulze discovered that by leaving a bottle filled with chalk, silver and nitric-acid by a window the sunlight would turn the chemicals on the exposed side a darker colour. Schulze then attached paper stencils to the outside of another glas enabling the covered areas to remain white and the uncovered areas to darken. Schulze published details of his disovery but it was much later that his work became relevant to the development of photography.
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