How did Louis Daguerre develop a latent image on an iodized silver plate?

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Alfred Stieglitz: Child with Striped Dress (Younger Raab Child) — History of photography *Child with Striped Dress (Younger Raab Child)*, autochrome photograph by Alfred Stieglitz, 1907; in the Art Institute of Chicago.

Louis Daguerre discovered that a latent image forms on a plate of iodized silver after it is exposed to light in a camera. To make this image visible, he developed the plate by exposing it to mercury vapor, which settled on the exposed parts of the image.123

This process significantly reduced the required exposure time from hours to approximately 20 to 30 minutes. Initially, the resulting images were not permanent, as the unexposed areas of silver would darken when subjected to light. By 1837, Daguerre perfected the daguerreotype by using a solution of common salt to fix the image, effectively dissolving the unexposed silver iodide and making the photograph permanent.123