Movie Makers (Jan-Dec 1931)

598 Perfecting projecting DOUGLAS H. TRAFTON NOVEMBER 1931 Like genius, it means an infinite capacity for taking pains THE object of this article is to stress the importance of perfect projection and at the same time to emphasize the care every projector should be given. This care cannot help but improve screen results. One of the first things is to prepare the projector for a show. This means to go over the entire mechanism and thoroughly oil all moving parts. The importance of oiling cannot be put too strongly. Because of the intense heat which emanates from the lamp housing, the oil tends to become thin and lubrication is necessary after about every 2000 feet of film has been shown. There are many different kinds of oils which may be used but usually the manufacturer has a special oil which is recommended for the particular projector. In no case should anything but the very finest of oil be used on either camera or projector. Equally important is cleaning of the lens and aperture plate. Because of great magnification, any particle of dirt on aperture or lens will be many times enlarged and give the picture a fuzzy appearance. Most any soft, lintless material may be used to clean the aperture plate since the latter is made of metal and is not easily scratched. The cleaning of the lens is a bit more exacting. Even materials which appear to be soft are often scratchy and should never be used. It is much safer to use special lens cleaning tissue which may be obtained for small cost from most photographic dealers or direct from lens manufacturers, bound in convenient book form. Another factor which should be given consideration in tuning up the projector is that of illumination. So many take it for granted that the light source is always correct. This attitude should not always be assumed even if a prefocus filament lamp base is being used. For almost every projector on the market, there is a special lamp with a spe .Arthur A. HeUcrt, ,lr cial filament. For example, a lamp designed for one projector may not work properly in another or vice versa. These lamps are designed by engineers in electrical laboratories and will only give their full amount of illumination at one point. Checking up on this point occasionally will give a considerable increase in projection quality. In general, unless a special optical system is provided, nothing less than the 200 watt rating should be used when the 16mm. picture is to be more than thirty six inches wide. Direct lighting exceeds indirect lighting since a certain amount of reflected light is absorbed by the plane surface of the reflector. The projector is now ready for starting and, at this time, there are a few things that should be given thought. After a projector has remained unused for one or more hours, it is termed cold. A machine in this state will start more slowly than one which has been running for a half hour or more. This is because the oil has become slightly stiff and, until it is warmed up, more power is required to operate the mechanism at the proper rate of speed. For this reason, it is advisable to have a speed control which will reduce the power as the mechanism limbers up. On the majority of projectors, this speed is controlled by a rheostat; on others it is governed by a friction clutch. By all means, a projector should be equipped with some type of speed control or presentations will lack uniformity. When thoroughly accustomed to the mechanism, it will be possible to thread a cold projector, start it and, as the mechanism warms up, step down the power little by little and maintain uniform speed throughout the entire reel. Many projectionists are able to tell by the sound of the motor just how fast the film is traveling. Others can tell by watching how the picture looks on the screen. A very useful accessory which will afford the user no end of benefit is a small opaque shutter known as a douser. This may be made by the projectionist or may be purchased for a small sum. From a piece of tin or aluminum five inches in length and two [Continued on page 616] The importance of oiling cannot be put too strongly