Motography (Apr-Dec 1911)

November, 1911. MOTOGRAPHY 213 By uniting leader and tail, an endless film band is produced with which the picture may be repeated as often as required without removing the film from the machine — a convenience where but one picture is projected or where a machine may be employed for each separate picture. If, however, there are more reels of film than machines to project them, the matter of removing the used coil of film and the threading up of a new one is easily accomplished, the coil thus removed being ready to put back for projection without rewinding in any way. The claims bear upon the arrangement of the filmcoiling spools in the magazine 20. No. 997,899. Projection Screen. Oswald Buechner, Zurich, Switzerland, assignor by direct and mesne assignments to Prana Gesellschaft fur Tageslicht-Projektion mit beschrankter Haftung, Hamburg, Germany. The object isa screen for projecting pictures during the day, or in a fully lighted auditorium. The invention is based upon two characteristic features ; on the one hand a pane of transparent material of suitable shape, constituting the projection screen as a whole; and on the other hand, the peculiar treatment to which the pane is subjected. The arrangement may consist of a single pane, or may be built up of a number of panes. The surface of the panes is given local refractive and dispersive properties by means of lens-like grainings. The panes are covered with a thin metallic coating, or a similar coating, the purpose of which is to reduce the amount of light reflected from the pane into the eyes of the spectators so that the pane will have a dark appearance in daylight. For producing such a coating, the inventor employs platinum. The same purpose may be effected by applying a coating of dark coloring matters. '7/\ ni t.ji ! 1 1 ti!'1 |L~ ! 1 1 11 l this way, the light of a picture, when transmitted through it from a projecting apparatus will be dispersed by the diffracting units in such manner as to cause the projected picture to appear on the screen, where it may be observed by the spectators, and if the screen then is treated by the thin coating of coloring matter referred to to reduce the reflection of external lights into the eyes of the spectators, so that the screen has a dark appearance in daylight, the predominance of the projected picture over the reflected light is emphasized. The claims of the patent are as follows: 1. _A projection screen of transparent material, having its image-display surface made up of associated refracting units of curved configuration. 2. _A projection screen of transparent material, having its image-display surface made up of justaposed lenticulae. 3. A projection screen of transparent material, having its image-display surface made up of uniformly distributed associated refracting units of curved configuration. 4. A projection screen of transparent material, having the image-display surface made up of identical juxtaposed lenticulae. 5. A projection screen of transparent material, having its image-dispay surface made up of associated refracting units of curved configuration, said screen having a coating adapted to reduce the amount of light reflected from the screen into the eyes of the spectators. The criterion to be followed in choosing the substances is that they shall give the pane a dark appearance in daylight. When a sheet of transparent material is prepared in No. 998,571. Automatic Film-Protecting Screen or Flame Shield for Motion Picture Projection Machines. Adolph F. Gall, West Orange, N. J., assignor to Thomas A. Edison, Incorporated, West Orange, N. J. Two figures accompany this review of Mr. Gall's patent, the right-hand picture showing the face view of the automatic shutter as viewed from the lamphouse. and the left-hand picture showing a section through the centrifugal device which controls the action of the shutter. The object to be accomplished is the shutting off of the light from the film in the film window when the motion head stops. Note that it is a question of shutting off the light when the motion head stops, and not when the film stops, in case the two should not occur at the same time. The shutter, 6, has a counterweight 35 upon it which keeps the shutter normally in front of the film window. When the mechanism of the projecting machine is turned, the little weights 17 are thrown out from the shaft by the speed of their revolution, forcing the friction plate 23 into frictional engagement with the shutter 6, thus frictionally revolving the shutter 6 out of the path of the cone of light from the condensers. When the motion ceases, the friction is released, and the shutter moves back in front of the film window under the weight of its counterpoise 35. There are thirty-one claims, some of them very broad in their scope. The following are specimens : 1. In a kinetoscope provided with a projection aperture, a screen normally covering the said aperture, means for moving it