Sound motion pictures : from the laboratory to their presentation (1929)

TELEVISION 349 mit scenes taken in ordinary sunlight. The necessary brilliance at the receiving end is furnished by a series of amplifying tubes. Again, most of the machines in this country are limited to a capacity of 40,000 light impulses a second. The situation is that of a motion picture projected at half the rate of the regular speed. Professor Karolus of Berlin has been able to project on a 3^-inch screen because he has increased the speed to 80,000 per second. He believes that it is possible to speed up this maximum even further. If the reader is to have some notion of the problem in this connection he must bear in mind that to transmit a fourinch square picture would require 160,000 impulses. A device for the transmission of moving pictures by radio, however, in which the size of the image transmitted is not limited, is reported to have been developed by a Luxembourg scientist in Paris. Although the transmission and reprojection of film by radio has been accomplished by various methods, the inherent limitations of previous experiments have prevented them, too, from assuming commercial importance. It is claimed that with the device of the Luxembourg savant the perfection of the image that is reproduced increases with the size of the screen. The use of a positive film is eliminated; the transmission is accomplished by using the negative film directly. This elimination is said to be an important consideration in the rapidity with which pictorial news items, for example, can be displayed after the original has been taken and the negative film developed. Most of the transmitters now used are for pictures bearing twenty-four to forty-eight lines to the inch. The clearness of television pictures depends upon the number of lines to the inch, since those having more lines are more distinct, as in the case of a half-tone. Each television picture consists of a series of lines. These