The Moving Picture World/Volume 1/Number 1/Lantern Slide Making
Lantern Slide Making
Lantern slide exhibitions, so very popular a few years ago, have suffered greatly by the advent of the moving picture shows. There is no better method of illustrating a lecture or song, or for studying pictures, than by projecting a good lantern slide upon the screen. We say a "good slide" advisedly, for it is our belief that the wretched work which is too often exhibited is largely responsible for the waning interest in these shows. In this department, therefore, we propose to print a series of articles on lantern slide making, so that our readers may learn what a good slide is, and be able to make one when desired. While there is much similarity between a window transparency and a lantern slide, there is this difference, that a bad slide may make a good transparency and vice versa. A transparency must be brilliant, clear and contrasty, because the direct rays of light pass through to the eye and the image must be strong to modulate the light. In viewing a slide, the light must pass through the slide, then spread over a white surface, then be reflected back to the eye, thereby losing in power, so the image on the slide must be far more translucent, or soft and flat, in comparison to a transparency; there must be little, if any, clear glass, and none except in the very highest lights, while the shadows must not be too dense to pass their proportion of light. Professional slide makers generally make their slides too contrasty; they may be pretty to look at, but when viewed upon the screen are tiresome to the eye and disappointing because not true to to nature.
The first requisite towards making a good slide is the proper kind of negative. This should be rather thin and full of detail, and the sharper the better. Given a good negative, a lantern slide can be made from it either by contact, as in printing a piece of paper, or by copying it in a camera. The first method requires that the negative subject be of suitable size, while, in copying, the subject may be enlarged or reduced. In making a set of slides it is advisable that the figures or subjects shall be of uniform size all through the set, therefore the copying method is the best. However, good slides can be made by contact, and if the negatives have been made with this end in view, it is the easiest and quickest method.
There are several makes of lantern slide plates on the market, all good, only some are more sensitive than others, and we recommend the slower brands to start with. A printing frame a size larger than the negative used is necessary, and in this should be placed a piece of clean glass, fairly thick, so as to avoid breaking the negative. The film or glass plate negative is then placed upon this glass, face upwards, and a lantern slide plate adjusted into the desired position. The negative must be carefully dusted, as any particle of dust would show as white spots on the screen and also endanger the breaking of the negative when the back of the printing frame is closed. The negative and lantern slide plate having been placed in contact and the printing frame closed, it is held up to the light of a glass jet for about five seconds, at a distance of six or eight inches. The lantern slide plate is then removed from a frame and developed like a negative, after which it is dried, masked and bound with a protecting cover glass.
Various kinds of developers give different effects, and these will be treated of at length in future articles.