Spirit photography has been created using various techniques, each with its own unique process and methodology. While some methods utilize cameras and equipment, others rely solely on the medium.
Standard Spirit Photographs
The standard spirit photograph originated in the 1860s and is created by a spirit photographer, sometimes with the assistance of a medium, in a studio environment. The sitter would position themselves in front of the camera, ready for the photograph to be captured. The photographer would then take the picture, and after development, the photograph would show one or more spirits present. The spirits could appear in a number of forms, ranging from full or partial body figures to just faces. Notable spirit photographers include included William H. Mumler and Frederick A. Hudson.
Mail-Order Spirit Photographs
The mail-order spirit photograph originated in the 1870s and is created by a spirit photographer, sometimes with the assistance of a medium. Unlike standard spirit photographs, the sitter was not present during the photo process. Customers would send a personal item, like a self-photograph or lock of hair, through the mail to the photographer. The photographer would place the item on a table and take a picture of it. The developed photograph would then display one or more spirits, which could appear as full or partial bodies or just faces. Notable mail-in spirit photographers include included William H. Mumler and William M. Keeler.
The skotograph originated in the 1900s and is created by a medium without the aid of a camera, usually in the dark. The term was coined by Spiritualist Felicia Scatcherd, derived from the Greek word “skotos” meaning darkness. The plates used for the photograph would either remain unopened or be stored in a black box or envelope, to protect them from light. The medium would then hold the plate between their palms or wave their hands over it. The developed photograph would reveal the presence of one or more spirits, writing, or other similar effects. Notable skotograph makers included William Hope and The Falconer Brothers.
The thoughtograph originated in the 1890s and is created by a medium, often without a camera. This type of photograph was influenced by spirit photography but not related to Spiritualism. Mediums would project or “burn” their own or others’ thoughts directly onto photographic plates or film. The developed photograph would show one or more spirits, writing, objects, or similar effects. Thoughtography was investigated and endorsed by Japanese professor Tomokichi Fukurai in his book “Clairvoyance and Thoughtography“. Notable thoughtograph producers include William Hope and Charles Lacey.
 Some Questions and Answers on Spirit Photography – 1895
 Woodhull and Claflins Weekly – Dec. 9, 1871
 Light – Sep. 17, 1921
 The Theosophist – Nov. 1936