COPYING.
the many applications to which photography may be put, perhaps there is not one more useful than copying. 8o far as the mere reproduction of detail goes, photography excels in accuracy the work of the most skilful draughts man. For copying old and valuable engravings, woodcuts, and line drawings, for the reproduction of diagrams, maps, and plans, its aid is invaluable. But probably the first work of this kind which the beginner will attempt will be the copying of a photograph, for although many people will not submit themselves to the tender mercies of the amateur portraitist, yet they do not mind handing over their " counterfeit presentment " to him in order to get it copied. It is by no means a difficult matter to copy a photograph, but it is not so easy to make people understand that the copy, in most cases, will probably be somewhat inferior to the original. However, this is not always so, for if the original happen to be an old and faded silver print, a very great improvement may sometimes be effected in the copy.
The essential matters to be attended to may first be roughly enumerated, each one in turn being subsequently considered in detail. First, and of chief importance, the 9 lighting of the subject to be copied ; secondly, the employ ment of a suitable plate ; thirdly, a special system of development.
The picture or photograph which is to be copied may be simply secured to a wall, or to a drawing-board, with draw ing-pins, but the work will be very much facilitated, especially if any great amount of it is in contemplation, if a special copying apparatus be devised. Such an arrange ment as that which I am about to describe may be easily constructed, and at very little cost. Its size will of course depend upon the nature of the work which is to be under taken, but the dimensions given will enable originals lip to 2 ft. square to be copied up to the half-plate or any less size. A piece of nicely-planed board 1 in. thick, 4 ft. 6 in. long by 11 in. broad, should be procured, to form a base-board. To one end of this a drawing-board should
be securely screwed with two iron angle brackets at right angles. To this the print or photograph is to be attached with drawing-pins. Sometimes, however, the print or picture to be copied is bound up in a volume. In such a case the book may be secured to the drawing-board by means of two strips of wood and four screw clamps. We must now devise some means of fixing the camera, so that when in position the lens will point to the centre of the drawing-board. Procure a piece of half-inch board the exact width of the base of camera, and 12 in. long, bore a hole in the centre to admit of the camera screw, now attach two other pieces as side supports, allowing about 4in. to project on each side so as to keep the base of the camera perfectly square. Now screw down to the baseboard two long strips of wood, just far enough apart to allow the camera support to slide stiffly between them. The diagram to be copied having been pinned up, the camera is screwed to the support, and the focus roughly ascertained by sliding the arrangement backwards and forwards, the fine adjust ment being effected with the rack and pinion.
The best lens to use for copying is the rapid rectilinear, although a wide-angle rectilinear is sometimes more con venient, as it enables the camera to be placed nearer to the object to be copied. It is very necessary to focus accurately. This should be done with the full opening of the lens, after which a, small stop should be inserted in order to get the sha-rpest possible definition to the margba of tbe plate ; f/32 I usually find sufficient for the pm-pose. If the copy is to be the same size as the original, the camera must be racked out to twice the focal length of the lens used, the lens being placed at the same distance from the object to be copied. If a larger sized reproduction is required, the lens must be nearer to the original ; or, if reduction is required, the distance between the two should be increased.