The international photographer (Jan-Dec 1936)

Twelve T 1 1 INTERNATIONAL PHOTOIiKAPH E R J.nnmry, W36 Television In England By Alan Lawson (Chief Cameraman of Baird Television) Telecine Electro Scanner for the transmission by television of talking pictures with a definition from 100 500 lines. IN 1934 the British Government formed a |2§lij Television Advisory Committee to seek an answer to the problem as to what system should be used for Television transmission. In February 1935 they published their report with these recommendations: To build a Television station, with Baird Television Company, Ltd., working on 240 line definition and Electrical and Musical Industries Ltd., working on 405 line definition, each supplying a set of scanners. The Advisory Committee recommended that all patents relating to Television reception should be laid open for all set manufacturers. The site picked for the first Television Station is situated in North London — at The Alexander Palace. The Di pole Aerial will be some 650 ft. above sea level. The Transmitter to be installed there will be of the ultra short wave type working on approximately 6.5 meters, with an output of 17.5 Kilowatts. The service area of this station will be close on 40 miles radius, which means that the whole of Greater London will be given a chance to receive Television programs that are expected to commence in the New Year. This is a short summary of the apparatus that will probably be installed by the two companies: Baird Television Company, Ltd.: Spotlight Scanner. This is the older method of Television Scanning known as The Flying Spot Method. It consists of a moving spot of light which passes over a subject and the reflected light is picked up by photoelectric cells and then amplified. The method is used for announcing, lectures, etc., and is capable of televising three quarter length figures. Telecine Scanner. Consisting of a continuous projector turning at 25 pictures a second, a 60 hole disc revolving at 6,000 r.p.m. the light source being supplied by a 60 amp. arc. This Scanner is used for Transmitting Films. Intermediate Film Scanner. A direct pick-up method of Television, using a motion picture camera, sound recorder, developing machine, scanning gate and sound reproducer. The same type of disc and arc are used on this machine as on the Telecine Scanner. The total delay period of this Scanner is 30 seconds, (the time from actual taking to actual scanning) accounted for thus: 5 seconds developing, 3 seconds washing and 15 seconds fixing; the remaining 7 seconds are taken up in the film travelling from one bath to the next. The film used is a Panchromatic stock approximately the same as the non-Super Sensitive Pan. Lighting, make-up etc., for this method, is the same as the usual film studio procedure. This Scanner can be moved into a normal sized truck as used by news reel companies and thus becomes almost as flexible as the news camera. Its limitations are the same as the standard motion picture camera, which are comparatively small. All the scanners mentioned so far have been of the mechanical type. We come now to those known as Electrical Scanners. The Electron Camera. This was invented by Philo Farnsworth in Philadelphia. It consists of a high aperture lens focusing an image on to a photo-sensitive plate which in turn produces an electronic image on the anode of a dissector tube. The electron image is moved electrically over an aperture to produce the scanning movement. Thence the signal is amplified in the usual way. This scanner can be used either for Telecine work, (thus displacing the Scanning disc) or for direct pick-up on interiors or exteriors, as is the Intermediate Film Scanner. Now we come to the E. M. I. installation which Baird Television, Ltd., Crystal Palace Studios. Intermediate film scanner, for use on interiors or exteriors. Please mention The International Photographer when corresponding with advertisers.