(W. Whately Smith)
SPIRIT photographs have long been a source of controversy and discussion, and signs are not lacking that public interest in them is at least as keen as ever. A Society for the Study of Supernormal Pictures has, for example, been formed recently, and it is by no means uncommon to meet people who owe much of their belief in Spiritualism to the results they have obtained through photographic mediums. This considerable public interest would alone suffice to make the subject important, but, apart from this, it is clear that if all—or even a fraction—of what is claimed be true the phenomenon must be of unique value from the point of view of strictly scientific research.
Photographic phenomena differ from practically all others studied by psychical researchers in being, so to speak, permanently objective. If one could be sure that the results obtained were not due to trickery one would be in a far better position as regards the problems of their origin and so forth than one is in the case of other types of “physical” phenomena. One could collect spirit photographs, compare them with one another, correlate their differences with the varying conditions of their production, and generally study them at leisure—a procedure which is not possible with table-levitations, materialisations, or direct-voice phenomena.[1] The photographic plate would, in fact, be the most powerful of all weapons of research if only we could eliminate all possibility of fraud. This is, as usual, the crux of the whole matter, and, as my collaborator and I hope to show, it is not nearly so easy to do as might appear at first sight.
Spiritualists commonly assert that photographic phenomena are easier to control than any others, and this is in a sense true. They would be easy to control IF one were allowed to take the necessary precautions. But one is not, and under the conditions which actually prevail at photographic séances the procedure lends itself to fraud more readily, and in more diverse ways, than any other form of mediumistic activity. Photography is a comparatively complicated process, and
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 at every stage there is opportunity for the astute trickster to produce the effect he desires. Part of the proceedings, moreover, must take place in a light which is inimical to accurate observation, and it should not be forgotten that, as a rule, the “sitter” is immobilised and placed hors de combat, so to speak, for an appreciable period while his photograph is being taken. (The significance of this will appear later.)
The various fraudulent methods which are or may be used and the question of the reliance which should be placed on the statements of those who believe that they have watched the proceedings so carefully as to exclude the possibility of fraud will be discussed at length later in this paper. I may as well say at once, however, that I see no reason for believing that any spirit photographs are, or have ever been, due to any cause other than fraud.[2]
But before discussing the various considerations which appear to justify this view I should like to make it clear that I, personally, am very willing to be convinced if and when adequate evidence is forthcoming. The question of what kind of evidence should be considered adequate is one which will be easier to answer after the various possibilities of fraud which must be eliminated have been pointed out. So far as I myself am concerned, I am prepared, further, to admit that photographic phenomena appear to me to be less improbable on general a priori grounds than many other alleged events of supposedly supernormal origin. We know that the camera can detect, or rather that the photographic plate is sensitive to, ether waves which produce no effect on the retina of the human eye, and it seems, on the whole, less improbable that “spirits,” if they exist, should produce subtle and relatively minor etheric disturbances of this kind than that they should be responsible for the movements of gross material objects in the way which is often claimed for them.
I maintain this merely to guard, so far as may be possible, against the accusations of prejudice which will doubtless be brought forward by some readers. A priori considerations of this kind have their legitimate place, but it is on the relevant facts that our final decision must be based. On all the relevant facts. This is the important point. It may be a “fact” that some great wise and eminent man states that he took such and such precautions, “never let the plates (or slides) out of his sight,” and so forth, but it is necessary to take into account, along with such statements as this, other facts about the psychology of deception, the reliability of witnesses, the potentialities of fraudulent methods and so forth which are usually ignored by enthusiastic devotees of the subject.
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One does not wish to be too dogmatic, there may be such things as bona fide spirit photographs, and when satisfactory evidence is forthcoming one will be very pleased indeed to make the amende honorable and acknowledge one’s fault.
But in view of the many methods of trickery which are available and the known incapacity of untrained observers to detect fraud the evidence at present available seems scarcely worthy of serious consideration.