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.
766. While lantern-slide plates are frequently made from microscopic enlargements, yet, owing to the lack of distinct sharpness to the very edge, slides made from these plates do not always give satisfactory results, and as the slide itself is many times enlarged when thrown upon the screen, the image on the slide does not require such enormous magnification.
767. By means of an ordinary long-bellows camera and a small-size lens, such as a No. 000 Goerz Dagor, which has 2 3/8-inch focus, the specimen on the microscopic slide may be enlarged sufficiently for lantern-slide use and every portion of the specimen can be made critically sharp. Of course, where minute parts of a section of the specimen are desired, the enlargement will need to be made through the microscope; but very often fair-sized sections of a specimen only are required. In such cases the use of the ordinary long-bellows camera fitted with a small-size lens, such as the Goerz Dagor, will serve best.
768. A simple method for enlarging a specimen is illustrated in Fig. 2, Illustration No. 122. Herein you will observe the specimen slide is attached to an ordinary piece of cardboard, which latter contains an opening slightly larger than the outside measurement of the specimen itself. The opening should be about the size of the cover-glass, which is about 3/4 of an inch. The specimen may be attached to the cardboard by means of pins inserted through the cardboard at an angle, at the top and bottom of both ends of the slide, just sufficient to hold the slide in place.
769. If one has a copying-board arranged as described and illustrated for Negative Enlarging and Lantern-Slide Making in Vol. V, then all that will be required is to insert the cardboard in the printing-frame and place the latter in the slide provided for holding it. You are then ready for the enlarging. If, however, you are not equipped with this outfit, Fig. 2, Illustration No. 122, shows a very simple method for copying that will enable one to produce as good results, requiring, of course, a little more care in adjusting the camera to the proper stage so that it may be on a perfect line with the slide.
770. An ordinary table may be employed for the purpose of receiving the slide-holder and the camera, as the instrument is more easily adjusted when working on a level surface. Begin the work by first placing the slide-holder (or printing-frame containing the slide) on the edge of the table before the window. Place the camera on a line with the holder. Draw out the bellows very nearly its full length; adjust the front-board by raising or lowering until the lens faces the exact center of the slide or that portion of the specimen you wish to reproduce. Arrange the camera so that the lens will be located about three inches from the slide, and with the bellows drawn to almost its full length you will find, upon focusing, that you will have an image large enough for a lantern-slide. The longer the bellows extension, of course, the larger the image will be on the ground-glass, and the shorter the focal-length of the lens the closer you can work to the subject, and as is usual, the smaller the size of the lens the shorter the focus; therefore, a lens only sufficiently large to cover the size object which you have to photograph is required.
771. If only microscopic slides were to be reproduced, the smallest size lens made could be employed. But there are other uses to which the lens can be put - for instance, the photographing of larger objects than those contained
Microscopic Slides for Lantern-Slide Work. 385 in the microscopic slide - and the one lens can be made to answer for all purposes. Therefore, we recommend the No. 000 Goerz Dagor lens, with an equivalent focus of 2% inches, covering a plate 2 3/8 x 2 3/8, as that will answer every purpose. This lens permits of working quite close to the object. It also allows of the use of the ordinary hand camera with good bellows extension.