So if a spirit photograph is to be classed as possibly genuine, the spirit may either appear self-luminous and cast no shadow, or may appear to be illuminated from the same point as the sitter, and cast a shadow on the background, if the latter be of a suitable nature to show it. But on examining a collection of spirit photographs taken by various professional mediums, we find that as often as not the spirit and sitter are lighted from opposite sides; or that a spirit face with a well-marked shadow on one cheek throws no shadow on the background. If our reasoning be correct, we can at once write such productions down as frauds. The photographs I produced at my Cambridge _séances_ show both these faults; two of them have the spirits lighted from the opposite side to the sitter, and one has the spirit lighted from the correct side but throwing no shadow, whereas the sitters throw clear shadows on the wall behind. In the other photograph I managed to get both the lighting and the shadow of the spirit correct; but in order to get the shadow I had to photograph the background with the “spirit”; hence when the sitters were photographed on the same plate there was a double background, which necessitated a rapid destruction of the plate! Of course the average medium does not consider these points at all; his sitters are usually satisfied with anything they can get, so why should he worry? But an intelligent observer examining a number of spirit photographs with regard to these points will quickly satisfy himself that the majority of them _can_ only be frauds.[10] There are a number of other points by which a spirit photograph may betray its method of production without reference to the conditions under which it was taken. Many spirit extras are simply copies of existing photographs, which are usually camouflaged in some way. Draperies may be substituted for the hair, or the features slightly retouched. A common method is to reverse the original photograph, right for left; a number of Hope’s productions were recently published in a monthly magazine, and alongside them life portraits of the “spirits,” the letterpress emphasising that, though undoubtedly the same face, they were different photographs. On examination with a mirror, however, the photographs were seen to be identical, and careful measurement of the faces showed the proportions to be exact. In the photographs more recently published by Mr. Bush, who laid a trap for Hope into which the latter appears to have fallen, the spirit was not reversed, nor was even the rather peculiar attitude of the head in the original photograph altered. A little spirit drapery was added round the face, and the whole thrown slightly out of focus; it is really a most clumsy piece of work, and should deceive no one.