> > > >

1948-49 Theatre Catalog, 7th Edition, Page 546 (531)

1948-49 Theatre Catalog, 7th Edition
1948-49 Theatre Catalog
1948-49 Theatre Catalog, 7th Edition, Page 546
Page 546

1948-49 Theatre Catalog, 7th Edition, Page 546

television lines are recorded on the film and will be seen as a region where a gap or overlap occurs making a white line for under exposure or a black line when an over exposure occurs.

Electronic Exposure Con'l'rol

An alternative method of exposure control is available in the form of a method of biasing the kinescope image on and off by an especially generated blanking signal so that exposure is precise. The camera shutter is replaced by an exposure control circuit initiated by a contact on the camera. The contact closes after the film has been transports ed and registered. The bias of the normally cut off kinescope is then removed which causes exposure of the film. The control unit, being actuated by the horizontal driving pulses, counts 526 lines (i.e., to the end of the 525th line) returning the kinescope bias to cut off ending the exposure. Here then we have a system which does not require synchronism between the camera and the television signal. The incoming signal supplies the keying information so the position of the blanking of the kinescope can change in phasing, but the exposure duration will always be correct because the information is obtained from the television signal. A slow change in speed between incoming signals merely displaces subsequent exposure period.

The basic problem in recording the images, is one of accuracy, imposed by the fact that three adjacent fields are supplying the information for the alternate film picture frames. Referring again to the time sequence diagrams, this fact may be readily seen if we start a scan in the middle of field "A" and continue to field ffCi, we have completed a picture frame in the required \1/30 of a second, but you will see that information has occurred in three successive fields and the scanning must be accurate for this duration.

The start and stop of the exposure, with either shutter or the electronic system is made during the viewing time; a critical comparison is being made on adjacent television lines so that any none interlace or shading will easily visible. If a picture splice occurs in the center of one frame it will occur during blanking in the next frame, there the comparison of exposure difference is between the top and bottom of the picture where it is not critical.

Rapid Processing

The next unit of a film system is the rapid processing equipment. The Eastman Kodak Company has found that rapid. processing, at' elevated solution temperatures, is entirely feasible with the hard positive and negative printing stocks which are now available. The film generally used for this purpose is a fine grain positive stock normally used for theatre release prints. This film is the Eastman 5302 or DuPont, and fortunately is the most reasonably priced film available. Kodak have constructed and demonstrated a rapid processing machine and made the information available to the industry. The film does not suffer from poor grain or other supposed ills of high temperatures and the process


is especially adaptable to the high gamma film developing required. 20th Century-Fox, Paramount, and Warner Brothers have experimental equipment of this type for evaluation purposes.

Film Proieci'or

The final link in the film system is of course the standard 35mm motion picture projector. The camera, the rapid processing machine and the projector are so coupled together to form a continuous film path and of course for programming flexibility they can be operated independently.

The two television systems can now be summarized in the following tabulation giving the advantages and disadvantages of each.


Performance wise the large screen projectors are now limited by the quality of the signals available for projection. The capabilities of the projection

FIGURE NUMBER 6. Television time cycle diagram.

system are equal to the best studio television equipment and of course any deterioration of the signal between the

camera and the projector causes an inferior picture on the screen. Experience has shown that large screen- images produced by both the direct and intermediate systems are entirely acceptable to critical audiences.

A television system for theatre use will no doubt be a closed system on ultra high frequencies and may not be subject to the band width limitations of the 6 megacycle channels used for television broadcasting. The equipment and techniques of operation will continue to be improved to bring high quality television programs to the theatre.

FIGURE NUMBER 7. Comparative tabulation of direct vs. indirect projection of television.


Direc'l' Proiecfion

Method High intensity projection kinescope with highly efficient refiective system.

Advantages 1. Appeal of immediate reproduction. 2. Simplicity of operation of equipment.

3. Low operating expense except for kinescope replacement.

Disadvantages 1. Optical system characterized by short throw. 2. Special screen required.

Intermediate Film

Method Motion picture recording of tele vision image followed by rapid

film processing and projection in

standard film projector. Advantages

1. Uses standard film projection equipment with present screen brightness.

2. Programming can be scheduled to best advantage.

1. Permits editing of film.

4. Permanent film record made available for s u c c e s s iv e shows and syndication to small theatres.

Disadvantages 1. Cost of installation. 2. Operation cost; a) Film b) Processing c) Personnel 3. Sound must be recorded.

Note: Cost is oflsct because film revenue

can be obtained by repeat showing.

1948-49 Theatre Catalog, 7th Edition, Page 546