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1954-55 Theatre Catalog, 12th Edition, Page 267 (231)

1954-55 Theatre Catalog, 12th Edition
1954-55 Theatre Catalog
1954-55 Theatre Catalog, 12th Edition, Page 267
Page 267

1954-55 Theatre Catalog, 12th Edition, Page 267

with equal and like signals from all three tracks measure voltage between the remaining wire of networks 1 and 2 and networks 1 and 3. The phasing is correct if the voltage read is zero, or very small, compared to the signal voltage at any network input,


All of the manufacturers of sound heads for CinemaScope will supply units, for magnetic reproduction, which will be mechanically placed between the upper magazine and the top of the picture head casting. This means that, with a composite film, sound will lag the picture rather than lead as is now the case. 'In order to accommodate the variety of projectors, a sound-picture displacement of 28 frames has been standardized.

The 28 frame displacement is correct when the intermittent pull-down is half way between the end of frame pull and the beginning of the pull for the next frame. No allowance has been made in the amount of offset to take into account the time of sound travel to the average audience location in the theatre, it being considered better practice for the projectionist to thread the film in such manner as to correct, if necessary, for the specific house. Each frame represents about 46 feet. For the sound to arrive at the screen speakers ahead of picture, the film length between picture gate and magnetic pickup head must be shortened. This correction can be made at the time of head installation when the film path must be adjusted for the particular projection machine model.

A new leader (Figure 11) has been devised with the correct locations of the picture start-mark and a corresponding sound synchronization mark. Inspection of this leader will disclose that the sound is in fact 28 frames behind the picture, and for CinemaScope release, the projector and sound-head should be carefully threaded so that the picture start mark is framed in the aperture, the sound start is lined up with the centers of the magnetic pick-up heads and suitable loops provided. The identification frames indicate that the sound is magnetic and therefore must be threaded through the magnetic head. The only other changes in this leader as compared to the present standard leader are that the 11 foot mark has been eliminated although the 12 feet for projector start is still maintained; and there is one additional foot provided at the tail for run-out. Clear diamonds are provided 28 frames following each footage mark, so that the film can be threaded in the projector for quicker start times than the usual 12 feet. These latter synchronizing marks are not labelled and, if the projectionist finds he must use them, and although there is little chance for error, he must be sure to use the corresponding picture and sound indications so as to maintain synchronism on the screen.

As indicated above, any presently produced product can be run on a. projector which has been correctly modified for CinemaScope release; and when optical sound release pictures are being exhibited, the film can be threaded through


the magnetic head so as to by-pass the mechanical filter and magnetic pick-up heads. Each manufacturer will provide suitable rollers to achieve by-pass but undoubtedly each will do it in a different way and the projectionist must determine at the time of installation the recommended threading process for the specific unit installed in his houSe.

When the machine is threaded for magnetic tracks the photographic sound head can be by-passed by threading directly to the sprockets with sufficient loops taking care that the film does not scrape anywhere. The exact threading used to by-pass the scanning point will vary with each kind of sound head,

CinemaScope film can be spliced but the splicers must be modified to have register pins suitable for the film. Film splicer manufacturers have been informed of the required changes and will have available new equipment. or modification parts for this purpose.

Two precautions must be observed when making a splice. First, both ends of the splice must be scraped because of the magnetic tracks which are applied to the base side of the film.

The second precaution is that an excess of film cement should not be used in making the splice since some of the tracks dissolve very readily in existing film cements; with excessive use of cement, the tracks will bleed or dissolve at and around the joint. With the careful application of cement, a good mechanical splice can be made without damage to the magnetic tracks.

Thirdly, the scraping should be such as to provide as little possible open space between the ends of the magnetic tracks which are joined. Spaces between tracks are points of no signal and usually make very little noise. However, if the space is unduly large, the splices will be audible. If it is found that the splices have a clearly audible low frequency thump or ffpop," it is probably due to parts of the splicer having become magnetized and the operation of making the splice induces a low frequency signal in the magnetic track.

The solution to this problem is to demagnetize, or degauss, the critical parts of the splicer or obtain parts which are made of suitable non-magnetic materials.

Little attention has been paid, in the past, to proper adjustment of the takeup. This is a bad condition and must be minimized but it must be made clear that the requirements of CinemaScope are not unique in this regard. The condition has been particularly aggravated by some recent installations for 3-D using fast starting types of motors, and removal of fiywheels. The takeup should be adjusted to provide just adequate tension at the end of the 2000 foot reel so as to keep the tension at the start of the reel within the sensible limits. Proper attention to maintain smoothness of operation is also helpful or the exhibitor may elect to purchase some of the newer and better takeup equipments.

There are many items of theatre equipment maintenance and film handling practice which can cause severe film damage and too often these have been given little attention. The film producer and distributor can do only so much in this regard and the remainder is up to the theatre personnel,


An attempt was made in composing this material to include as much detail as seemed necessary, but without burdening the reader excessively. Emphasis has been placed most on new items and others, about which general knowledge exists, have been treated more generally. The engineering advice of 20th CenturyFox Film Corporation is available to all exhibitors, suppliers, equipment and service companies. This Company is anxious to cooperate on any problem pertaining to the exhibition of CinemaScope which will further the best possible presentation in the theatre. The Companyis prime interest in CinemaScope is to be of benefit to the industry, the exhibitor, the producer and the equipment supplier.

THIS STILL from the 20th-Fox production. "Untamed." illustrates the tremendous amount of action that can be encompassed in a single Iong shot. This is one of the many virtues of CinemaScope process.
1954-55 Theatre Catalog, 12th Edition, Page 267