DOUBLES A popular form of freak photograph, showing two pictures of the same person on one plate, as, for example, a man playing cards with himself, etc. This kind of picture was at one time (188o) somewhat popular among professional photo graphers, but the work is now almost exclu sively confined to amateurs. Each half of the plate is exposed separately, thus allowing the figure to be taken twice on the one plate. Many methods of making such exposures have been advocated and a few accessories placed on the market, but excellent doubles may be made with the simplest of fittings.
For the partial lens cap method a lens cap is made of blackened cardboard, as A, the ring C being made to fit easily the front of the lens, and then covered on one side with blackened cardboard B from which a segment is cut off as shown at A ; exactly how much to be cut away should be found by trial. Having cut away a very small portion, the partial cap is placed on the lens and the picture examined on the ground glass. The cutting away must be con tinued until one half of the picture is dark and the other half lighted. The dividing line as seen on the screen will not be cleanly cut, but will have a diffused or vignetted effect. About the proportion shown on the right-hand side will have to be cut away, certainly not one half of the card, as might be supposed. During the cutting, the cap is revolved on the lens mount so that both halves of the view can be seen, and when one half vignettes or merges into the other a trial plate may be exposed. It requires accu rate cutting to allow of one exposure merging into the other, and to prevent the join between the two separate exposures being distinguished. If, for example, a thin under-exposed band shows down the centre of the plate the covering part B is too large, and not enough has been cut away ; if, on the other hand, there is a dense over-exposed strip, the aperture A is too large, thus causing the centre to receive a double exposure. To use the cap, it is placed on the front of the lens with the opening on the right hand side, as in B, and the sitter is then posed and focused on the half (left hand) of the screen on which the picture is seen, exposure shutter set, dark-slide put in, and the exposure made in the usual way, the shutter of the dark slide being drawn out all the way. For the second half, the camera must not be moved, the slide is closed, taken out, and the partial cap revolved to the opposite side—that is, to the position shown at C. The sitter then assumes a position that will be visible upon the second half of the focusing screen, the partly exposed plate is again inserted in the camera, and the second exposure made on the unexposed half of the plate. Obviously the two exposures
must be of exactly the same duration. For this method the camera must be provided with a shutter working behind the lens.
If the camera has no shutter, and exposures are made by removing the cap, a cut cap cannot be used. The circular card from which the segment has been cut off, and without a ring can be fitted into the lens hood itself, and of course covered over with the ordinary cap with which the exposures are made.
Another favourite plan of making doubles is to fix a card in the reversing back of the camera (see D), the card being blackened and of a size to cover one half of the plate. The first exposure is made with the card at B, so as to photograph the half marked A ; the card is then removed to A in order that the remaining half of the plate B may be exposed. The card used at the back needs to be cut even more accurately than that used in the lens, because being so near the plate the dividing line between the two expo sures is more clearly cut. It is desirable to select a background with vertical lines which will not clearly show the division—a bookcase or a door, for example—and the inevitable line between the two parts of the image is so arranged that it coincides with a strongly-marked natural line in the view.
Another accessory (somewhat analogous to the first method described) is shown at E. This is a box of very thin wood, blackened inside, about 6 in. long, 3 in. deep, and 4 in. high ; it has a round hole cut in the centre of the back part so that it may be fitted on the front of a lens and used as a kind of partial lens cap. The front of the box is fitted with a sliding panel or half lid, which slides across the front in grooves, allowing each half of the plate to be exposed in succession. Over all there is a proper lid which serves as a cap. This box front is used after the manner of the partial cap, and the exact width of the sliding panel can only be found by experiment as before, one side of the sliding panel being cut accord ingly. The latter may be worked by a knob on the centre of the panel itself, or by means of a wire.
In all cases it is advisable to arrange the whole scene first, and to allow the sitter to try both positions, examining the ground glass carefully to see that all is included, and that no part of the sitter—feet and legs, for example—gets beyond the centre, or the whole effect may be spoilt.
A style of " double " portrait (two or more positions at one sitting and with one exposure) is that known as a " polypose portrait."