The developing of positive film is a process much similar to that we have just described for the negative film. The chemicals used in the formulas are much the same, though the proportions vary. As positive film is less sensitive to light than negative, the developing need not be done in a dark room, though even here daylight, or the “yellow” light of the common electric bulb, is not permissible. To the eye positive and negative film appear much alike, and, in truth, they differ only slightly to render them more adaptable to their different uses. The drying of both positive and negative film, following the various operations, is accomplished by means of large drums, on which hundreds of feet may be wound. The picture producer may now decide to tint some portions of his film and to tone others. Tinting is nothing more than giving the film a bath of dye; toning is a chemical process by which the dark portions of a picture are intensified and given certain color tones, while the high lights are not affected. Though photography at night is now attempted very frequently, tinting is the means more commonly employed to give the impression of action taking place at night. Toning does not appear so artificial as tinting, since it does not affect the high lights, and an artistic director may easily arrange his scene so that the coloring appears natural on those parts that are affected. The toning of film is accomplished by placing it in chemicals which affect the silver deposits on the surface, permanently changing its color. Where there is no silver deposit, as, for instance, in the snow-bank we have so often mentioned, there would be no change. The process of fixing follows. It might be well to explain here the usual method of photographing subtitles and other explanatory reading-matter in a picture. This is done by means of an ordinary camera using glass plates, which points downward at the subtitle, which is in white letters on a black background. What is known as a “plate-printer” is then used to put this impression on the positive motion-picture film. In this process the transparent negative of the subtitle secured on the glass plate is placed in a cabinet between a condenser lens and a smaller projecting lens. Before this small lens there is a film-gate, the positive film being fed into it in the same manner that we have seen employed in the camera and the positive-printer for ordinary work. Thus when the light passes through the condenser and the negative of the subtitle, the small lens casts a reduced image of it on the small bit of positive film passing before the gate. In ordinary printing of motion-picture film negative and positive are superimposed and passed before a light; in this case the image cast by the small lens takes the place of the negative film, but the principle is the same.