Barthes use of the term eidolon (an insubstantial image, spectre, phantom) brings to mind the spirit photography practiced by spiritualists in the past two centuries. Spirit photography got its start in 1862 when William Mumler made the first spirit photograph. The premise of spirit photography is that departed spirits imprint their images on pictures. The spirits appear as faint, ghostly images floating besides the living subjects.

The photograph on the left is a classic example of traditional spirit photography taken by William Mumler around 1865.

The practice of spirit photography makes literal Barthes injunction that every photograph contains "that rather terrible thing which is there in every photograph: the return of the dead" (Barthes, p.9, 1980) But what it also does is reverse the temporal flow of the photograph. The image is no longer just about the past but about a possible future in which we will all be reunited with those who have departed. Spirit photography opens up the possibility of multiple temporal vectors; past, present and future all coexist in time so that the time is never out of joynt.

Not surprisingly, spirit photography was at its most popular following both the American Civil War and the First World War when mourning would produce a desire to resurrect the dead.

The principles of spirit photography remained relatively stable over the latter part of the 19th century and the early part of the 20th century. Curiously, the ethereal entities did not appear during the early period of photography (beginning in 1839): there were no spirit daguerreotypes, ambrotypes or early tintypes. Indeed, not until double exposures were made possible by the advent of photographic paper prints from glass-plate negatives, did the spirits choose to make their photographic debut. Mediums would take the glass plates and put them through a procedure known as 'pre-magnetisation'. This, in short, meant keeping the plates close to the medium's body and may have been inspired by the theories of animal magnetism espoused by mesmerists. The sitter would then have their photographs taken by the medium whose psychic powers allowed so-called 'psychic extras' to appear in the developed photograph.

Spirit photography is still practiced today but not so much in the manner outlined above. Today's ghosthunters are more interested in phenomena - orbs, ectoplasm, strange lights.

For examples, see:

Spirit Photography APS online exhibit
http://www.amphilsoc.org/library/exhibits/spirits/intro.htm

World's Most famous Spirit Photographs
http://www.prairieghosts.com/grphotos.html