Now for the slides. These require some artistic talent, but not a vast amount. If a youth has a vein of comic talent, it will add to the fun, or he may easily procure prints from which to copy. Some, however, prefer scenery, natural objects, etc., all of which, if well painted, show well in the magic lantern.
First procure the glass, cut to the size required, so that it will slip easily into the opening in the lantern; then trace the outline, after having the colors ready, which can be purchased of any artists' colorman.
Observe that the dry colors must be ground very fine, and mixed with spirits of turpentine, and worked in with mastic varnish. Especial care must be taken that enough varnish be used to moisten the color sufficiently, and prevent its being limpy while working on the glass; also great judgment is necessary in laying on the colors, as they ought to be as transparent as possible.
In the event of the picture being humorous and a part of it movable, the latter must be managed by a long slip of glass affixed to the slide, previously framed round—for instance, a barber shaving a man. The whole of the painting should be executed on the slide, except the barber's arm, which must be traced and colored on the narrow slip, and then arranged so as to complete the figure. This is easily done, by the slip fastening into the frame. Then by a quick movement of the narrow piece of glass, backward and forward, while exhibiting, an appearance of reality is given, and the operation of shaving is successfully performed.