. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. weenthe two nozzles, on which revolve two arms with a shutter atthe end of each, which can be moved out of the way whennot required, but are adjusted to give the required flash before the scene comes on. Personally (my experience being,however, very small, and quite as an amateur in thesematters), I prefer to trust to the hand alone, held in frontof the nozzle before the light is turned on, and which can bewithdrawn in an instant, and with no risk of failure. Tinters may add very much to the
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. weenthe two nozzles, on which revolve two arms with a shutter atthe end of each, which can be moved out of the way whennot required, but are adjusted to give the required flash before the scene comes on. Personally (my experience being,however, very small, and quite as an amateur in thesematters), I prefer to trust to the hand alone, held in frontof the nozzle before the light is turned on, and which can bewithdrawn in an instant, and with no risk of failure. Tinters may add very much to the pleasing effect of plainphotographs, if used with suitable subjects. Thus, a warmtint is easily thrown over a foreground, and a blue tint overthe sky, or sea and sky, or on a moonlight scene. Tintersare of two kinds. Fig. 68 shows the most common. It fitson the nozzle of the objective, and any different colours canbe fitted in the top and bottom shutters, while an opaqueshutter outside can also be folded down, so as to graduallyextinguish the picture altogether. LANTERNS AND THEIR MANIPULATION 121. This is a favourite attachment to the single lantern also,as the screen may be darkened while the slide is instan-taneously changed; for it maybe taken as a universal rulein lantern exhibitions, where effect is any object, that thetohite screen should never beshoivn. To do so makes theslides appear much less brilliantthan if no such bright lightintervenes. The other plan is to cut slitsthrough the sides of the lanternbody near the front, so that largepieces of coloured glass, or gela-tine films between two glass plates, can be slid in and out of the lantern close to the backof the condensers. This plan is more costly, and weakens thelantern, but has an advantage in not interfering with definition,as the edge of a glass plate in front of the objective does to asmall extent. But the saving of light mentioned in somecatalogues only exists in the imagination of the apertur
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Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
