The Optical Magic Lantern Journal (April 1894)

67 The Optical Magic Lantern Journal and Photographic Enlarger. A Simple Means of Registering Lanterns. A coMMON trouble with many lanternists seems to be ‘‘ how best and simplest to register my lantern.” Although various means have from time to time been suggested in our back numbers, perhaps the following will be found to be as quick and certain a way as any. This method is one adopted some time ago by Mr. H. Wood, 13, Sturdy Road, Albert Road, Peckham, S.E.,who, we believe, has lately been fitting this attachment to the lanterns of many of his fellow lanternists. Mr. Wood lately brought to our office the fronts and explained in a few words how quickly the necessary adjustment for registration could be made. It might be well here to say a few words respecting the meaning of the registration of lantern fronts, especially as we are constantly adding new readers to our already large list, ° and it is quite possible that some of them may like to hear a few words as a groundwork. If a single lantern only be used, all that is required is to place the slide in front of and close to the condenser, making it as central as possible. Now, if a bi-unial is to be employed, it follows that it will be used for making the views dissolve into one another, or for producing effects in which two slides are projected upon the screen at one and the same time. These two slides we will suppose to be daylight and moonlight scenes. As is well known, these two slides will be exactly the same in outline detail, the difference being for the most part in the | colouring. The day scene being on the screen, and it being desirous to change or dissolve it to | the moonlight one, it follows that these two | ' to pass through and become clamped by the slides must fall with mathematical precision upon the same parts of the screen, so that when both are projected they will practically have the | appearance of one picture. When both are on, the former is taken off by, say, lowering the light, thus leaving the second slide in view. In order to get this effect of the two slides falling on exactly the same parts of the screen two things are necessary. The slides must both have the same relation to their frames, and the frames must be placed in the same relation to the condensers. We will deal first of all with the method for | : been done, the adjustable stop alluded to at side registering the lanterns themselves and then speak of the slides. It will first be necessary to obtain templates, which may be two frames, each containing a glass of the same size that is used for lantern plates; in fact, a good thing to use is an ordinary coated lantern plate. These two glasses should be firmly fixed in their frames, so as to prevent the slightest subsequent movement. This having been done, it next becomes necessary to scratch a line across each plate on the gelatine side by means of a carpenter's gauge; the same is done from the end of the frame, so that we have two marked plates or templates precisely the same in every particular. Care should be taken to mark the side and ends from which the measurement was taken, for when using them in the lantern that side must lie on the runner and the end must butt on the stop. Having the templates prepared, it is by no means a difficult matter to register the | lantern. Now to refer to the lanterns ; in the position ; shownin Fig. 1 (electric) terminals are secured in position on the plates by being secured by screws from the back of the plates as at aa. A runner is then constructed of brass about the width of aslide frame, and to it attached at right angles, two stout wires of sufficient length terminals as shown in Figs. 2 and 3. These runners having been fitted to the various stages of either a double or a triple lantern, we next light up and place one of the templates in the stage, there being a small screw stop fitted at the side (not shown) to prevent the frame from going more than a certain distance, the other template is placed in the other lantern. One or other of the ends of the runners are now adjusted and clamped at Aa until the horizontal lines which were scratched upon the gelatine template are exactly overlapping. This having of the lantern is set so that when each frame is taut against it the upright lines of the templates are, like the horizontal ones superimposed. When this has been done the lantern is what is called registered, and we now come to the