Spirit photography was first used by William H. Mumler in the 1860s. Mumler discovered the technique by accident, after he discovered a second person in a photograph he took of himself, which he found was actually a double exposure. Seeing there was a market for it, Mumler started working as a medium, taking people’s pictures and doctoring the negatives to add lost loved ones into them (mostly using other photographs as basis). Mumler’s fraud was discovered after he put identifiable living Boston residents in the photos as spirits.
Through the 1880s into the early 20th century spirit photography remained popular, with notable proponents such as Arthur Conan Doyle and William Crookes. William Stainton Moses, another spiritualist, claimed that spirit photography operated by means of a fluid substance called ectoplasm, in which the spirits take form.
One of the later spirit photographers was William Hope (1863–1933). The psychical researcher Harry Price revealed that the photographs of Hope were frauds. Price secretly marked Hope’s photographic plates, and provided him with a packet of additional plates that had been covertly etched with the brand image of the Imperial Dry Plate Co. Ltd. in the knowledge that the logo would be transferred to any images created with them. Unaware that Price had tampered with his supplies, Hope then attempted to produce a number of Spirit photographs. Although Hope produced several images of spirits, none of his materials contained the Imperial Dry Plate Co. Ltd logo, or the marks that Price had put on Hope’s original equipment, showing that he had exchanged prepared materials containing fake spirit images for the provided materials.
Hope went to great lengths to clear his name, including writing a book supporting spirit photography. His name was never cleared.