The Cine Technician (1935-1937)

Fetj.-Marcli, 1937 The Joiir)ial of the Association of Cine-Technicians 159 Technical Abstracts Applications of Photography Details of recent patents taken from Plioto^^rdphic Abstracts, Vol. XVI., Part 4, No. 64, published by The Roval Photographic Society of Great Britain. Motion Picture Cameras. P. D. Brewster. ( cuncras for two or three separate films, one directly in front of a lens and the others displaced to left and right of it, have two intermeshing multiple-bladed rotary mirrors and a rotary shutter enabling the exposures to be effected simultaneously and uniformly over the entire surface of each film. Kinetnatographic Cameras. Lampen-und .Mt-tallwaniifalir. R.Ditmar Geb.Brunner A.-G. In a camera having an indicator showing the lens diaphragm adjustment, visible in or near the field of the view-finder, adjusting means for the diaphragm, connected thereto by at least one transmitting element, is arranged at a distance therefrom, and within reach of the fingers of the hand holding the camera. Production of Coloured Picture Films. Ilainionicolor Films, Ltd. (J. Guardiola). The two sides of a photographic positive are diffcrenthdyed, one side with an acidified mixture of Malachite green, Brilliant green, and Rhodamine B, and the other side with a mixture of Rhodamine B and Auramine made alkaline, the two sides being mordanted in a solution of chromic acid and potassium ferricyanide acidified with sulphuric acid, and afterwards treated in a bath of sodium hisulphate. Multiple Printing Machine. .\. L. \'. C. Debrie. In a multiple printing machine for motion-picture work, a jilurality of supply and take-up reels are mounted one abo\e the other on a plurality of vertically arranged shafts. Power drives are connected to the shafts, and the printing operation takes place when films are drawn past a hollow cylinder having a light source inside the cylinder and having slots through which the light passes. Sprocket teeth are provided on a series of axially arranged drums for mo\ing the \'arious films. Method and Means for the Reproduction of Films. Projector A-G. {a) Photographic contact-printing apparatus especially for films of low light-sensitivity, has a feed track with a guide surface ciuved transversely of the film and wholly or partly concave towards the copying light. {b) The perforation gauge of the underlying film is made slightly longer than that of the overlying film in its untensioned state, and the films are so fed together through a comparatively long copying zone that the portion of the overlying film, which at a given moment is within the copying zone, is given a greater tension than the corresponding portion of the underlying film. Adjustment for Kinematograph Printer. M. A. Dalotel. Ihe rheostat rs formed of elements whose resistances have values which form a series of numbers so that by addition the series of natural numbers is formed up to the factor of exposure desired (32 lights with five elements) ; each of the sections can be short-circuited by a lever actuated by a perforation in a pilot band fed in synchronism with the film to be printed. Kinematography in Colour on Film Having a Trichromatic Mosaic. (i. A. Raguhi and .ste. Lunnere. Printing is done by projection from an original made on a film ha\'ing a trichromatic mosaic, the original image being twice the size of the copies. While each image is being printed, three-colour filters are introduced into the light beam, each for a suitable time, .so as to eliminate the radiation transmitted h\' two elementary filters of the mosaic. Noiseless Sound Reproducing System. J. H. Hammond, junior. For noiseless sound reproduction, the sound track is printed in two colours, one colour for the sound portions of the track which will actuate the reproducer, and another colour which will not actuate the reproducer, for the silent portions of the track. Printing Trichromatic Mosaic Images. Ste. Lumiere. In order to a\-oid loss of saturation of the colours due to overlapping of the spectral regions of the three elementary filters, the printing light is fihered by three practically monochromatic filters ; the relative exposures can be adjusted according to the composition of the light, the transmissions of the elementary filters, and the chromatic .sensitivitx' of the emulsion. Photographic Light Sensitive Material for the Production of Coloured Photographs. B. Gaspar. A bipack comprises one film having two superposed light-sensitive layers of different colour-sensitivity containing colour-forming compounds which produce different colours in the two layers, and another film having either one light-sensitive layer or two superimposed layers, the colour-sensitivity of which differs from that of the first film. The possible constituents of the layers are specified. Report on Studio Lighting S.M.P.E. Studio Lighting Committee classifies motion picture lighting broadly into two types, general and modelling. General illumination is flat lighting of fairly uniform value. For black and white photography it ranges from 200 to 400 foot-candles, and provides light to make the set photographically "visible" and to illuminate the shadows. Lighting units used to provide this light are twin-broadsides, the rifle, the scoop, and multiple-lamp overheads, and small lamps placed behind posts, trees, etc. 200-300 and 500 watt .short tubular projection type lamps are used in table and floor stands and wall brackets. On large sets, general lighting not being able to provide sufficient intensities at great distances, modelling units are used at their widest beam.