GB522163A - An improved process and apparatus for production of stereoscopic cinematograph films - Google Patents

Abstract

522,163. Stereoscopic kinematograph pictures. HATTANGDI, P. V. Dec. 2, 1938, No. 35143. Convention date, Sept. 2. [Class 97 (i)] Negative stereographic images are produced on a double-width film which is fed vertically, one frame at a time, through a camera having two horizontally spaced lenses, the film, after passing through one gate, 3a, Fig. 1, being looped to pass through the other gate 5a, and the gate and shutter apertures being so disposed that the partial images are formed in spaced relation in juxtaposed vertical rows. For centring the images, the camera lenses 7, 8, Fig. 4, may be adjusted by a wheel 9, or by tilting. The exposures are made through a rotating shutter 10, or a pair of coupled shutters, one for each lens ; and provision may be made in the camera for producing marginal marks on the film by exposure to light through prisms 16 and apertures in the shutter 10 and film gates. The marginal marks are printed with the pictures on to the positive film, and are used in conjunction with photo-electric cells on the projector to give a warning signal if either the right or left hand pictures are not in their normal positions at their respective gates. The positive may be of double-width, printed or reversed from the negative film, or it may be a single width film, Fig. 7, printed with the pictures in alternating sequence. The printed marks are shown at 32. This single width positive may have the left and right hand pictures in spaced relation along the film, and may have only one pair of feed perforations for every two frames, in which case the intermittent feed mechanisms at the two gates of the projector or their teeth are staggered by one picture frame. This arrangement of feed perforations may also be used for the doublewidth positive film, Reference is made to a similar camera for producing the negative images in alternating sequence on a single-width film.