Home Movies and Home Talkies (Jun 1933-May 1934)

424 HOME MOVIES & HOME TALKIES duction of a piece of the 17|-min. film showing both pictuie and sound track. Notice that the perforations cut into the comers of the picture frames, and therefore to prevent the holes showing on the screen and at the same time to utilise the maximum picture area the corners of the pictures are roimded by means of a mask in the gate. The apparatus itself is well depicted in GUI' illustration ; the feed and take-up reels are made to take a thousand feet of 17^-mm. film, which is equivalent to 800 ft. of 16 mm., and therefoie one reel will last approximately twenty-three minutes. This is a considerable convenience in two -reel comedies and the like, and saves a break in the middle of the film to change over the reel. An Interesting Feature One of the most interesting feattu-es about the new apparatus is that the same lamp is used for both projection of the picture and illuminating the sound track. The lamp used is a 16-volt 8-ampere tyjDe, consumption thus being 128 watts, a transformer being used to step dowTi the voltage from 110 (that for which the motor is woimd) to 16. Most of the light from the lamp is concentrated upon the film in the gate, and the picture obtained is a good bright one. As demonstrated to us both in Paris and in London, it satisfactorily fills a screen far larger than ever M'ould be used in the home. Illumination of the picture gate is direct, the lamp being immediately behind the film, but some of the light from the lamp goes at right angles to the path of the light to the film, passing lapwards through a concentrating lens on to the sound track slit. Passing through this, it reaches a small mirror placed at an angle, and by this mirror is reflected into the apertvire of the sovmd-head. which is placed to the left of the j^rojector proper. Inside the sound-head is a photo-electric cell and amplifier. The volume is controlled, not as is usual by a resistance as in the ordinary type of volume control, but simply by a rotatable shutter which is made to cover more or less of the opening as required, thus reducing or increasing the light falling on the cell. A knob to control the shutter, and therefore the volume, is plainly seen in our illu.stration. This ingenious system works excellently in practice and gives a progressive variation of sound from the maximum right down to inavidibility. The Film Path The path of the film from the feed to the take-up reel is clearly seen in our special drawing. In it we notice that the film ])asses first of all over rollers to the lower side of a fairly large sprocket, and after the formation of a smaU loo]> proceeds through the normal picture gate. From this is passes round the underside of the lamphouse, uj) a guide at the back, and over a roller comiected to a large flywheel (this being used to remove any last traces of irregular motion due to the passage through the intermittent gate). The film overhangs this roller slightly so that concentrated light from the lamp below can be passed through the sound track and up to the min-or. After this the film proceeds to the upper side of the sprocket under which it was fed before reaching the picture gate, and then goes to the take-up reel. The arrangement of the sound -head as a separate vmit from the projector and the reflection of the light by means of a mirror into an aperture has the advantage of separating the soundhead mechanically from the projector mechanism and is in some ways similar to the scheme used in the Mihaly professional apparatus. The box containing the sound -head also Enlarged picture of the Pathe 17i-mm. sound-on-film, showing sound track on left. (" Home Movies " photograph) includes an amplifier consisting of a screened grid valve and a pentode, together with the necessary transformers, etc. The total consumption of the apparatus, including projector, lamp, motor and amplifier, is, we are informed, only about 2^^ amperes, therefore the apparatus can be run satisfactorily off the ordinary electric light mains provided a transformer is used. The aj^aratus as designed is not .suitable for operation on direct current mains. In operation the apparatus runs smoothly and is reasonably quiet even without any screening box, threading is particularly easy, and the necessary controls are conveniently to hand. The reproduction of the films we have had the opportunity of hearing is of high quality, speech being crisp and clear, while the bass frequencies come out well. The only apparatus additional to that we have described is the loud-speaker, which is placed immediately adjacent to the screen. We understand that a better speaker than that we heard will be provided with the outfit. The speaker is included in the pi*ice mentioned— £60. At 25resent the plans are to place this apparatus on the market in the auturon, by which time a considerable library of sound films will be available. Messrs. Pathe have wisely decided not to market the apparatus before such a library is available, and we vmderstand the films will be hired out at a price approximately the same as that charged for library hire of silent pictures of the same length. The films will also be available for outright purchase if desired. All the film will, naturally, be non-inflanunable. Our only regret is that the makers have thought fit to utilise the IT^-mm. size instead of the 16-ram. size, which has been standardised for all other somid-on-film projectors. The technical advantages of the 17i-mm. size have been given above, but the great disadvantage is of course that there will be no interchangeability of films between the v'arious sound projectors, and a separate and distinct library will have to be got together for the new size. Furthermore, 16-mm. sovmd-on-film amateur cameras will shortly be appearing, and films taken with these cameras will not be usable on the Pathe projector. At the same time the general design of this apparatus is so good that we see no reason why it could not be altered to take the 16-mm. size, thus bringing all the projectors and library films into line, and enabling amateurs to show their ovn\ 16-mm. silent films in this projector. THE PATHESCOPE GAZETTE NEW 9|-MM. NEWS-REEL BEGINNING with April, Messrs. Pathescope, Ltd., are issuing monthly, through the usual dealers, the "Pathescope Gazette," a super-reel feature bringing professionally made news-reel pictures right into the home on 9|-mm. stock. The first issue will contain as sporting interest the Eton Boys' Sports and the famous water jump, the International Rugger Match, the Boat Race, and the Grand National — surely enough to satisfy the most ardent sportsman ! A number of other features of general interest will be included, and the price will be £1 12s. 6d. — or only five shillings more than that of an ordinary Super film. Ask your dealer to tell you when it is ready !