This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
The Camera. The only apparatus required is a camera that is large enough to take at least a 4 x 5 plate. A larger camera may be employed, however, but is not necessary. A tripod or camera stand may be used, but, as it is essential that all lines be accurate and distortion entirely avoided, a very inexpensive and convenient outfit can be made as follows:
Platform. Secure a smooth, planed board, about 12 inches wide, 3 feet long, and 1 inch thick. On each edge of this board, fit a strip lengthwise, to be used as guides for sliding the camera backward and forward; into this fit a platform or box as wide as the distance between the two strips, as long as the length of the camera to be employed and about 4 inches high. Bore a 3/8-inch hole in the center of the cover of the box and, with the regular tripod screw, attach the camera to this platform, making it rigid. This box or platform fitting between the strips on the board will insure perfect lines of the subject on the ground-glass. On one end of this board at the sides attach two upright standards, about 14 inches high. These standards contain a groove the thickness of an ordinary 8 x 10 printing-frame, used to hold the negative for copying, and which latter will be termed the negative holder. By means of this standard attached to the copying board, the negative will be perfectly perpendicular with the camera and on a line with the lens. If it is not on a perfect level with the lens raise the negative to be copied, by blocking up underneath the negative holder as much as is required to give you perfect alignment (See Illustration No. 20).
Preparing The Negative-Holder. If the largest plate from which a lantern-slide is to be made is 5 x 7 inches, provide an 8 x 10 sheet of ground-glass, or flow a piece of plain glass with ground-glass substitute. When the substitute is set and dry, which requires only a few minutes, place the glass in an 8 x 10 printing-frame and fasten it with one tack on each end. In case neither ground-glass nor substitute can be obtained, a very fine quality of tissue paper will answer, pasted over the outside of the printing-frame.
870. Place the negative to be copied in a 5 x 7 printing frame, film side out. Use thumb tacks to hold the negatives in the frame. Having attached the negative to the printing-frame, place this small frame inside the 8 x 10 frame, with the film side facing the camera. This will give a space equal to the thickness of the frame between the negative and the ground-glass (or tissue paper). This is important, as the distance between the two throws the ground-glass out of focus when the negative is sharp. The ground-glass, or tissue, serves as a diffusing screen and equalizes the light on the negative. To place the negative too close to the ground-glass would bring the latter in focus with the negative and give it a coarse grain. This is avoided by the thickness of the printing-frame providing a sufficient distance between the two to overcome this grain. The two frames are held together by means of a heavy rubber band around both.
871. Place the negative-holder in the grooves of the standard, these grooves being provided for this purpose on the end of the copying board, and arrange this board before a window with an unobstructed light, a north window preferred, when ready for copying.