We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Report of the Progress Committee 83
of fine lines have been cut through the silver is suggested as a suitable test object for testing projection lenses/^^
A cylindrical shutter rotating on a horizontal axis and positioned between the film and light source is claimed to reduce the heat at the gate aperture at least 6.5 per cent/^^ Several patents claiming certain novel improvements in shutter design have been granted/^*
B. Special Projection Equipment Sound Film, Projection. Approximately 2,500 sound projection installations had been made up to April 15, 1929, one firm reporting nearly 1,700 separate installations.^^^ The introduction of sound pictures has greatly changed the character of the motion picture theatre. All the technic of the motion picture has now become available to be added to the machinery of the drama.
Encouragement to the small exhibitor is offered by one firm which has announced sound devices selling between $3,500 and $6,000.^^^ Several types of electric turn-table reproducers have been made available, some of which are equipped with means for synchronizing the pictures and the sound. ^^^ A description has been published of a portable sound device for reproducing various sounds, such as airplane motors, machine gun fire, etc.^^^
A new design speaker working on an organ pipe principle has been described which is so designed as to be a decorative feature of the theatre.^®^ Minton and Maloff ^°° have dealt with recent developments in the design of dynamic loud speakers. A description of the equipment used for sound reproduction by Western Electric and details for its installation have been published by Scriven and Santee.^°^ Difficulties encountered in measuring the acoustic properties of loud speakers have been discussed by Bostwick,^^^ and by Engl.203
An indicator has been designed for sound picture projection which shows the number of feet per minute and the minutes consumed per thousand feet of film.^o*
New types of exponential horns have a conversion efficiency from electrical to sound energy varying from 10 per cent to 50 per cent in the frequency range of 60 to 7,500 cycles.^°^ A description has been given of a compact power amplifier designed to provide field current to a dynamic loud speaker, ^^^"^