Home Movies and Home Talkies (Jun 1932-May 1933)

HOME MOVIES & HOME TALKIES 25 youR CIHE QUERIE/ AN/WERED Free Service for Readers Islthere a cini problem bothering you P Have you soins difficulty in which you would like expert help ? Do you w.mt to know where to obtain certain apparatus and what it will cost ? HOME MOVIES is at your service in this and mmy other ways. Address your query to : The Service Department, HOME MOVIES, Messrs. George Newnes, Ltd., 8-11, Southampton Street, Strand, W.C.2, enclosing the free Query Coupon printed in this issue. Queries and answers of general interest will be printed each month on this page. All others will be replied to by post. Special Note. — Criticisms of amateur films, opinions of amateur scenarios and test of apparatus can be undertaken by special arrangement. In such cases a preliminary letter to the Editor is essential. This month we print a selection of queries received by the Editor and his technical staff up to the time of going to press. F. 1. fAs:ot) writes : " M7 cine projector gives exoellent results so far as lislit,definition and st3idia2S3 are concerned, but I find that when I fo3iis on a still picture the apparatus seems to ?o out o£ Jocus as soon as the motor is stirtei. Everything comes right again if I slightly re-focus on the moving film. Wiiat mast I do to put this right ? " Answer. — This difference bet\veen the focus of a still and moving film is characteristic of all projectors, although it is slightly more pronounced in some than in •others. How Makes Differ The different makes of projector vary slightly in construction but the general rule is to hold the film in the " gate " by some form of spring plate. Pressure on this plate is carefully adjusted, but it must not be too great otherwise excessive force will be required to draw the film through the projector with consequent damage to the film and mechanism. When the film is stationary it is held flat in the gate, as soon as it starts to move the spring plate is held back slightly and during the run the film takes an average position just slightly away from the surface against which it is held when still. Although this difference is extremely small it is sufficient to alter the focus and the lens must be readjusted accordingly. An Interesting Variation In one of the best makes of projector the gate mechanism is made with such precision that no back pressure plate is required, spring pressure being applied only on the side but even in these the focus of the stiU picture is sUghtly different from that of the film in motion. F. C. (Clapham) asks : " How can I tell whether my cine camera is loaded or not vpithout opening it and thus ruining the film, if any is there ? " Answev. — Unscrew the lens and tap the release a few times. If there is any film in the camera the creamy emulsion wUl show in the lens aperture while the mechanism is running. A few taps on the release will be quite sufficient to show this. If you see nothing but black you can be sure either that the camera is Do not unscrew your lens out of curiosity, only if you know it needs cleaning inside. When you do, look through the diaphragm, which should be perfectly clear of fluff or dust of any kind. empty or that the black " leader " paper has not run through. In any case, if you should open the cine camera in daylight you will not waste all the film, only33 or 4 feet will be fogged. I.ess tlian this will be fogged if you open the camera in a very dim artificial light. J.R. (Mill Hill) : " When examining one of my films just returned from processing, I find that in some cases where a scene in bright light is followed by one taken in the sliade and vice versa a frame or two at the end of one scene and the beginning of the next seems either over or under-exposed. I thought at first it was due to the shutter being a little slow in starting up, but I cannot understand why any change of shutter speed should happen the end of a run. The film projects quite well on the screen and one cannot see any fault this way, but it is quite obvious when examining it by hand under a magnifying glass. Is there something wrong with my shutter? " Development by Macliinery Anstver. — Such variations in the film are due to the use of the verj' ingenious automatic and electrically controlled processing machines by the big companies. By using special light-operated cells of the photo-electric type, wide variations in exposure can be compensated for in processing, but any sudden transmission from one type of lighting to another may i^hovi for a frame or two in the processed film and is no indication of a fault in the r.amera. The one or two slight disadvantages in this automatic processing are much more than counterbalanced by the numerous advantages as is evidenced by the very high level of excellence in the modern finished product. A Tip for " Fade-Outs' As you say, the slight variations rarely show on the screen, and the only noticeable case of trouble Avith this "form of processing is where the camera user tries to produce a " fade-out " bv slowly closing his diaphragm and thus' causes a progressive, under-exposure till all hght is shut off. Unfortunately the automatic processing machine manfully (or machinefully !) endeavours to compensate for this gradual under-exposure and while it succeeds in doing so for the first part of the space it has to give up in the end ! If much fading in and out is done it is better to use one of the positive-negative films rather than the re\-ersal t)-pe. One-Sided Focus The Rev. A. R. M. (Nottingham) vrates : " When projecting my Palestine film in the parish hall recently I found it to be badly [Continued on page'iS))