Wet Plate Collodion is a photographic process invented in the 1850s that uses a glass plate coated with a mixture of collodion and silver nitrate. This technique allows for the creation of detailed images, but it requires the photographer to work quickly, as the plate must be exposed and developed while still wet. The process produces either ambrotypes, which are positive images on glass, or tintypes, which are positive images on metal. Wet Plate Collodion was popular in the 19th century for its ability to capture sharp details and rich tones, making it a favored method among early photographers.