Harper's indoor book for boys

by Joseph H. Adams

If your negatives are larger than 3½ × 3½, and it is desired to get the entire picture on the slide, then the reduction process will have to be resorted to. For this work you can use your camera if it has a long bellows, and the work should be done in a room where a window is towards the north.

Obtain a piece of board five feet long and ten or twelve inches wide, and at one end of it erect the negative-board, as shown at Fig. 17. The negative-board or holder should be twelve or fifteen inches square, with an 8 × 10 rabbeted hole at the middle of it, and supported with two brackets, as shown at Fig. 17 B. Kits can be made or purchased to fit in the opening reducing to 6½ × 8½, 5 × 8, 5 × 7, 4¼ × 6½, 4 × 5, and 3¼ × 4¼. With this range of sizes any negative from 3¼ × 4¼ to 8 × 10 can be held in the board. Now arrange two strips of wood at each edge of the long base-board, so that the camera can slide forward and backward on a platform built to support it, as shown at Fig. 17 D.

The camera should be made fast to this moving platform with wood cleats and screws, and it should be mounted high enough so that the centre of the lens will be exactly on a line with the centre of the opening in the upright board, as shown by the dotted line in Fig. 17. At the upper corners of the plate-board arrange slim, steel-wire nails with the heads cut off, and bore holes near the ends of sticks three-quarters of an inch square so that they will fit down over the nails, as shown at Fig. 17 E. The other ends of the sticks should rest on the top of the camera. Over these sticks a dark cloth should be thrown when making photographs of negatives, to keep out light and prevent the high light from the window affecting the action of the lens.

To make a reduction of a large negative, fill the plate-holders with 3¼ × 4 lantern-slide plates, having obtained kits to fit your holders; then clamp a negative upside down on the board, as shown at A. Mark the lantern-slide size with a lead-pencil on the ground glass of your camera, taking care to centre it; then move your camera forward or backward and operate the bellows until the correct size has been obtained. Focus as sharp as you can; then stop down your lens with the smallest diaphragm. Experience will dictate the proper length of time for exposures. No definite rule can be laid down, for the varying conditions of light, rapidity of plate, and state of the weather—all will have to be taken into consideration.

Fig. 17. Fig. 18. Fig. 19. Fig. 20. Fig. 21. Fig. 22. Fig. 23.

Lantern slides made by reduction are always sharper and better than contact slides, and whenever possible they should be made after this fashion, even from films which may be held flat between two plates of clear glass. A piece of white tissue-paper should be pinned against the window towards which the camera points, so that a blank white light will be beyond the negative, thereby avoiding the possibility of picking up any false lights or shadows.

Lantern slides should always be masked, so that the actual sight-opening through which the lantern-light is projected will be two and three-quarters inches wide and two and a half inches high. A mask form can be purchased or made from sheet-brass. The opening and the other dimensions should be of the same size as the lantern-slide plate, or 3¼ × 4 inches. The masks should be cut from black needle-paper with a rotary cutter, having first prepared a number of the blanks of the proper size; then the openings can be cut as shown in Fig. 18. A smaller mask for the central part of slides can be made two inches wide and two and a half inches high, as shown in Fig. 19, and for portraits an oval mask is the best (see Fig. 20). Covering-glasses or crystals are necessary in making slides. Old lantern slides can be cleaned and used for this purpose, or some very thin, white glass may be cut into 3¼ × 4-inch plates.

To mount slides lay a mask against the film-side of the plate, or positive, and over this place a clean, clear covering-glass, as shown at Fig. 21. With binding-tape (which comes in white and black) first bind one edge, as shown at Fig. 22, arranging the paper tape so that an equal margin will be visible on both sides. Bind the opposite edge, and then cut away the projecting ends of the binding. Proceed to close the short ends in a similar manner, and as a result you will have a finished slide, as shown in Fig. 23. Some slide-makers begin at one corner and run a strip of binding all around the edge without cutting it. This is a little difficult to do at first, but if you have a clamp that has a compression-screw and will turn on its axle, it simplifies matters greatly. Some amateurs prefer black binding-tape, others white. The white tape with black masks makes a neat-looking slide, and if the margin is wide enough the title of the picture may be written on it.