To the MOTION PICTURE
INDUSTRY for 1931...
TWELVE MONTHS 0/ HAPPINESS and PROSPERITY «Sfc
HI TIT
SIMEON ALLER • WESLEY SMITH
and
DUPONT-PATHE FILM MFG. CO.
COLOR
with your Bell & Howell
A fact of interest and importance to cameramen and producers — your regular Bell & Howell Cameras can be used for the Bi-Pack color processes.
A special intermittent mechanism, an adaptation of the famous B & H pilot pin mechanism, is used to handle the two negatives. This unit is readily interchangeable with the regular, ultra-speed, or silenced mechanisms. Simply by changing this mechanism and, of course, the magazine and the film, any Bell & Howell Camera can be converted for color from monochrome, and vice versa, at a moment's notice.
The new mechanism is so constructed that the focal plane of the Bi-Pack films (which are run emulsion to emulsion) is in exactly the same position as the focal plane of the black and white film in the regular mechanisms. There is no necessity for any change or adjust- ment on the camera itself — the focusing ground glass is left in the standard position.
♦ ♦ ♦
The new Cooke Speed Panchro and Panchro lenses are also ideal for Bi-Pack color processes, as they are corrected to the wave lengths utilized by the Bi-Pack emulsions. Their special correction adapts them equally well for modern monochrome work with panchromatic film and incandescent lighting.
Write for further information on B & H Cameras or these new Cooke lenses.
BELL & HOWELL
BELL & HOWELL CO., 1849 Larchmont Avenue, Chicago, Illinois New York, 11 West 42nd Street • Hollywood, 6324 Santa Monica Blvd. London (B & H Co., Ltd.) 320 Regent Street • Established 1907
Veuillez faire mention de I'American Cincmatographcr en ecrivant aux announceurs.
1
An
Ultra-Mod ern Unit Perfected by Mole- Richardson, Inc.
If It Isn't An
Here is one of the newest mechan- ical contributions for the filming of talking motion pictures with sound proofed cameras » » » the Mole - Richardson Perambulator. With the use of bl imps a need has arisen for a camera mounting, w hich could be used tor either travel or stationary shots with equal facility. Mole- Richardson have solved the problem with the
unit pictured above Such
service is now taken as a matter of course by the industry. Over a period of years Mole - Richardson service has been anticipating the Studio requirements and will It Isn't An Inkie. continue to do so. » » » » »
MOLE- RICHARDSON
INCORPORATED
941 NORTH SYCAMORE AVENUE, HOLLYWOOD
Interior view of Mole - Richardson plant where incandescent lighting, electrical and sound equipment is fashioned and perfected for the motion picture industry.
2
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• AMERICAN ■
CINEMATOGRAPH ER
A Technical and Educational Publication, Espousing Progress and Art in Motion Picture Photography
|
HAL M 0 H R President, A. S. C. |
HAL HALL Editor-in-Chief and General Manager, A. S. SUITE 1222 GUARANTY BUILDING, HOLLYWOOD BOARD OF EDITORS: William Stull, Herford Tynes Cowling |
C. CALIFORNIA and Ned Van Buren |
EMERY HUSE Technical Editor, A. S. C. |
|
Volume XI |
JANUARY, 1931 |
Number 9 |
CONTENTS
Page
SCREEN DEFINITION, by Dr. L. M. Dieterich 9
"VERSIONS," by Geoffrey Shurlock 10
MACHINERY OR ART IN MOTION PICTURES,
by J. Tarbotton Armstrong 1 1
THE CAPTURE AND PHOTOGRAPHING OF VARANUS
KOMODENSIS, by Philip M. Chancellor 12
"NOISELESS RECORDING," by H. C. Silent 14
STANDARDIZATION OF PHOTO-ELECTRIC CELLS,
by N. R. Campbell _. 16
HAL HALL SAYS 18
AN INTERVIEW WITH LEWIS MILESTONE 19
AMATEUR MOVIE MAKING, by William Stull 30
ABOUT LENSES 34
Cover, by Russell Ball
FOREICN REPRESENTATIVES
Georges Benoit, c-o Louis Verande, 12 rue d'Aguessau Paris, 8e John Dored, Paramount News, Paramount Building, 1 Rue Meyerbeer, Paris IXe, France Herford Tynes Cowling, Eastman Kodak Company, Rochester, New York, Eastern Representative Harold Sintzenich, Eastman Kodak Company, Bombay, India
PUBLISHED MONTHLY by THE AMERICAN SOCIETY of C I NEMATOGRAPHERS. INC, HOLLYWOOD, CALIFORNIA Established 1918. Advertising Rates on Application. Subscription: U S., $3.00 a year; Canada, 53.50 a year; Foreign, $4.00 a year; single copies, 25c Telephone GRanite 4274 Copyright, 1930, by the American Society of Cinematographers, Inc.
3
CASTER GREETINGS
C First Again, As Usual J
THE NEW TANAR PORTABLE SOUND SYSTEM
COMPLETE OUTFIT PACKS IN THE
TWO CASES HERE SHOWN
WEIGHT 60 lbs. per case
SIZE 18x9x12 inches 20x10x10 inches
NEW AMPLIFIER •
NEW MOTOR DRIVE AND TACOMETER MOUNT •
NEW TYPE BATTERIES •
NEW TYPE CASES
TANAR CORPORATION, Limited
Originators of Portable Sound-on-Film Recorders
General Offices: 5357 Santa Monica Blvd. Laboratories; 1110-1112 N. Serrano Ave.
HOLLYWOOD, CALIFORNIA, U. S. A. New York Offices: Wafilms, Inc., 729 Seventh Avenue Telephone: HEmpstead 3939 Cable Address: TANARLIGHT
and HEmpstead 3362 Postal Telegraph Private Wire
4
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DOUGLAS FAIRBANKS
Endorses
TANAR
PORTABLE SOUND SYSTEM
to
ing T
IS
TANAR PORTABLE SOUND SYSTEM
TANAR CORPORATION, Limited
ORICINATORS OF PORTABLE SOU N D -ON - F I L M RECORDERS
General Offices: 5357 Santa Monica Blvd.
HOLLYWOOD, CALIFORNIA, U. S. A. New York Offices: Wafilms, Inc., 729 Seventh Ave. Telephone: HEmpstead 3939 and HEmpstead 3362.
Laboratories : 1 1 10-1 1 12 N . Serrano Ave.
Cable Address: TANARLICHT
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MAZDA --not the name of a thing, but the mark of a research service
Tour
CONFIDENCE
YOUR confidence in the quality, performance and leadership of General Electric MAZDA photographic lamps is justified. The sterling repu' tation of the General Electric Company and the z,eal of the famous MAZDA research service are exemplified in every G. E. MAZDA lamp in service in modern cinematography.
For every lighting task, general and specific, rely upon the superiority of G. E. MAZDA lamps. National Lamp Works of General Electric Com' pany, Nela Park, Cleveland, Ohio.
GENERAL ELECTRIC
M A Z D A it LAMPS
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loin us r- r\> General Electric Program, broadcas- t>zr\ Saturday evening over a nation-wide N. B. C. network
IUst i s I) t s
for a $ro£perou£ anb J|appj> J? e to Hear to our jHanp Jfrtenbs> #m *m #m
lit mbeeb is gratifying to refcrieto tfje ^ past pear conf ibent tfjat our Success is bue m great measure to tfte count- ies expressions of appreciation anb tJje lopaltp anb f aitf) of tfjose frienbs tottfjout tofjom our best efforts tooulb fjabe been of no abail s&
3n tf)is realisation, toe are glab at tf)is goob=toill Season to extenb to tfjem our Sincere greetings &g ^
Hafetn Corporation
1707 J^aub Street Hos Angeles, California Capital 5387
"3ff it's not a it's not silent!"
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Eight
AMERICAN CINEMATOCRAPHER
January, 1931
Cameras
Elmer C. Dyer, A. S. C.
Screen Definition
by DR. L. M. DIETERICH
Consulting Engineer
Part III
CONSIDERING influence of filter use upon definition, we want to dwell at first upon the optical characteristics of the carrier medium for a filter color or tone. Leaving gelatine filters for later consideration, glass as a carrier medium becomes of interest, the more so as its optical characteristics are the same for glass diffusion discs and have not been ana- lyzed in Part II, so prevent repetition.
It may be remarked here that they are also of interest when any glass plate is used in front of the photographic lens as, for example, in blimps.
The optical characteristics are shown in exaggerated relative proportions in Diagram No. 1 .
If O is the selected object point, it will image at I if lens system L produces a 1:1 magnification. If glass plate C is interposed between object point O and lens system L, then the sample light rays (six are shown), shown as dotted lines and converging at image point I are refracted by glass plate C and pass through lens system L as shown by full lines. They converge at image point I' which is identical to the image of ob|ect point O1, produced by lens system L if there were no glass plate C placed in front of the lens L. Analysis of this diagram shows that the distance 00' and relative distance II' increase with the thickness of the glass plate, or in other words, the focal value in general increases with the interposition of a glass plate between the object and the lens system. This increase is not only governed by the conditions above mentioned but results also in a decrease of the depth of focus for a given lens posi- tion for the following reason:
A scrutiny of Diagram No. 1 shows, as before mentioned, that for a given power of lens system L and a given separation between G and L, the distance II' increases with a decrease of the distance of object point O.
The practical results can be most clearly shown when we consider a normally extreme depth of focus which we get when the lens covers at universal focus position a great depth of object field.
For points O far distant from the lens, the distance II1 becomes very small and the circles of confusion controlling out-of-focus effects are not increased.
The closer O becomes to the lens, the greater becomes the distance II', the circles of confusion therefore increase and out-of-focus effects become apparent for ob|ect distances which are of acceptable focus without the presence of the glass plate.
Analysis of the optical characteristics of the light rays pass- ing through the plate shows, furthermore, (see diagram 2 1 that a full spectrum white ray is spectrumized by the glass plate according to the obliquity of the incident ray, the thick- ness of the glass plate and the refractive index of the glass forming such plate.
We have, therefore, another condition adversely influencing sharp definition by introducing chromatic aberrations which increase the residual aberrations of the well corrected lens system L.
The combined results as deduced from above analysis should be known to the cameraman in order to enable him to safeguard the definition results he is striving for.
It is, of course, supposed that the glass plate, be it used as a diffusion disc, a filter base, or a sound proofing element in "blimp" construction, is made of "optical" glass, i. e. with absolute parallel surfaces and of uniform optical material char- acteristics throughout.
But even under those best glass plate conditions the following facts remain:
(Continued on Page 26)
Diagram No. I
Versions
The Problem of Making Foreign-Language Pictures by GEOFFREY SHURLOCK
Supervisor of Foreign Production, Paramount-Publix Studios
PROBABLY the greatest single problem at present confront- ing the motion picture industry is that of properly serving foreign patrons. Until recently a motion picture — wherever it might be made — had a world audience to play to. The com- plete standardization of technical equipment made it possible to present a film in any movie theatre in the world. The only change needed to adapt a film to meet the needs of any for- eign-language group was the substitution of foreign-language titles for the original English ones.
With the coming of the talking picture, this has changed. Dialogue, no matter how sparingly used, is nevertheless an essential part of the picture, and to adapt a talking picture to foreign consumption, this dialogue must all be in the language understood by the various language-groups. It has been irrefutably proven that foreign-language dialogue cannot be "dubbed" into a picture made in another tongue. There- fore, if today's pictures are to play to the same world-wide audience they formerly entertained, separate versions of the film must be made for each language-group which is to be reached.
This gives rise to many problems, commercial, technical, esthetic, and psychological, which are as yet only half solved. The crux of the situation lies in the fact that the major part of the world's technical resources, both in men and material, is concentrated in Hollywood, while — despite that city's polyglot population — the majority of the outstanding foreign players are found elsewhere. The question therefore is: which group is it most advisable to bring to the location of the other; which arrangement will make for the most efficient production and the most satisfactory working conditions? In other words, which will make the best pictures?
It is a most perplexing problem, and one that will in all probability remain unsettled for a long time to come, for each solution has much in its favor, and much against it.
Viewed commercially, the plan of making all foreign- language pictures at the Hollywood studio has the advantage of speedier production, centralized control, and the availability of the vast technical resources accumulated through more than twenty years of intensive development. On the other hand, these advantages are offset by the considerable expense of importing and maintaining stock companies of actors, directors, and writers in five or six languages, and by the considerably lower costs of production in Europe.
Viewed technically, conditions favor the centering of for- eign-language production in Hollywood, for there are found both the most experienced technicians, and the greatest array of modern equipment. On the other hand, equipment may be transported to where the foreign actors are available, and in the major producing centers of Europe — France, England, and Germany — there are enough capable technicians to form, with perhaps the addition of some Hollywood-trained experts, the nucleus of an excellent producing organization.
Viewed esthetically, the question is simply: is the Art ot the Talking Picture sufficiently different from the Art of the Silent Picture to demand entirely separate production- treatment in order to appeal to the different language-groups (which formerly were equally receptive to the same silent production), or are the two sufficiently similar so that merely translating the dialogue, as formerly the captions were trans-
lated, will be enough to adapt a screen plot to meet the enter- tainment needs of the various groups?
Psychologically, the problem is to decide whether the un- doubted theoretical advantage of having every person in the company — from the director and star to the meanest assistant- prop-boy — working, speaking and thinking in the same lan- guage is great enough to be of practical value, or not.
Obviously, there are two equally good answers to each of these questions. Hence, each producing organization is attack- ing the problem in its own way. Some prefer one method, and some prefer the other. A few are even experimenting with both.
The Paramount-Publix Corporation, for instance, has, after some experimentation determined upon the plan of making the majority of its foreign-language product abroad, except in cases where the star or stars — like Maurice Chevalier, Claudette Colbert, or Marlene Dietrich — is of unusual international popularity, and capable of playing in two or more languages. In such cases, it is obviously best to make such foreign versions at as nearly the same time and place as the English version as is possible. In the majority of cases, however, it has been found best to treat the foreign versions as entirely separate productions, making them abroad, with casts entirely composed of foreign players, and at any time which is convenient.
Spanish pictures, however, may be made in Hollywood, due to the proximity of Mexico and Latin America. These countries not only furnish the necessary players, but also the largest market, which makes it advisable that the Spanish spoken in these versions should be of the Latin-American variety rather than that of Spain, which is not so popular with the people of these countries.
To provide facilities for making all other foreign-language films, however, we have found it advisable to create an en- tirely new studio near Paris. The majority of existing European studios were found to be inadequate for large-scale produc- tion, and since the installation of sound equipment necessitates practically complete rebuilding of a studio, it was decided that the most economical procedure would be the creation of an entirely new film plant. To this end we have erected a com- plete sound studio at Joinville-sur-Seine. In every respect this plant is new throughout, and represents the most modern pro- duction plant in the world, as it embodies the lessons gained during more than twenty years of activity at the firm's New York and Hollywood Studios. Six months ago the site was a wheatfield; today it is a large, modern production plant includ- ing nine sound-stages, laboratories, recording-channels, power- plant, administration buildings, carpenter, machine, paint, and other shops, and every other minute detail of a fully-equipped studio. The technical equipment is almost completely American, including such familiar units as Western Electric recording equipment, Mole- Richardson Incandescent lights, Bell & Howell and Mitchell Cameras, Paramount "Blimps," Moviolas, and many other familiar devices. The personnel, on the other hand, is largely European, although many of the department heads, and technical experts are either Americans, or Holly- wood-trained Europeans. The executives are all well known in America; the chief being Robert T. Kane, who is well known for his long and distinguished career in this country. His assist- ant is Richard M. Blumenthal, and the General Manager is (Continued on Page 22)
10
Machinery or Art in Motion Pictures
by J. TARBOTTON ARMSTRONG
Curator of Motion Picture Museum, University of Southern California
THE MOTION PICTURE is big business, and as such it is operated. The objective of big business is money, and everything is being done by the various companies to outstrip each other in getting more theatres and better equip- ment. But the theatres and equipment are really for the pic- tures— not the picture for the theatres and equipment. And besides, with the increase of education, public taste is improving.
The attempt to satisfy the intellect of a ten year old child is disgusting to the better educated portion of the motion picture audience. Likewise the producers forget that children are often the severest critics, and will detect fallacies in story development just as quickly as adults. What is more, the average child of today can understand almost all subtle develop- ments of plot. Even sex is not above the comprehension of many children.
While equipment may be improved, the quality of the aver- age production continues on the same level. The same plots are used over and over. The success of one picture will bring sudden releases of pictures of the same type from every studio. By the time the whole cycle, including quite a few inferior productions, is released, the public will be so tired of that form of picture that the best offering would not have a chance of success for some time to come. It would be far better if the studios would stop this duplication of types of pictures.
The reasons for avoiding duplication from the production standpoint may also be mentioned. In the first place getting a production ready in time to compete with another involves hasty producing. In the second place, it is impossible for all the writers at all the studios to get new ideas for the same topic at the same time. Ideas for stories do not come to order. In the third place, this attempt to imitate will often result in mis- casting, upon the principle that a picture of this type must be produced whether the acting talent be available or not. Much of this sort of thing happened during the recent musical comedy deluge.
There is a false standard of measuring the greatness of a production by the cost. The cost of the picture is often included as an advertising feature. But acting, directing, and photog- raphy are arts, and writing is likewise an artistic venture. A picture employing ten characters may be as great as a dramatic achievement, and a greater artistic achievement, than a spec- tacular production involving an expenditure of a million dollars (and expected to bring back three million).
There will always be some types of pictures involving heavy costs. With these pictures every care should be taken to have the result justify the cost. Mere pageantry will not satisfy the average audience. No matter how complicated the scenes, or how large the supporting cast, the story must be woven around a few main characters — and it must be a story, rather than an excuse for spectacle. Sometimes it is rather hard to keep the two together, but it can be done.
These spectacular productions, however, often come closest to the development of one thing generally missing in the average talking picture. This is rhythm. With the succes- sion of scenes involving massive movements, carefully photo- graphed, some rhythm must result. With poor sound con- ception and continuity the result, of course, would be not rhythm, but chaos. Likewise the intermingling of trifling dia- logue would shatter the rhythm of these big scenes. By this it is certainly not meant that the dialogue writer should give
pioneers, for instance, highly polished lines — but he should avoid lines which contribute nothing to the picture. Spectacular productions must depend a great deal upon rhythm for their success.
But other pictures also demand rhythm, and very few have it. Some may regard rhythm as artificial, but acting is, after all, artificial. No play or motion picture can depict every single incident that might happen in a slice of real life, and most certainly, every speech that might be spoken in reality can not be spoken on the screen.
Voices must be, for the most part, pleasing and harmonious. Every effort must be made to have what happens appear natural, but at the same time, the interest of the audience must be held. Actors should always remember that they are not speaking to a microphone, but to several million people, or rather, that several million people are watching their inter- pretation of their parts. They must also remember to keep their voices, as well as their bodies, in character. Of course racketeers and similar characters are permitted to have harsh voices, to a certain extent, but even they must speak distinctly.
But keeping voices in rhythm is difficult unless proper dialogue is supplied, and memorized. Much of the dialogue so far has been rather spasmodic. Besides the voices, the various sounds included in a picture must also be kept in rhythm, or the effect upon the audience will be jarring.
Lack of rhythm has been one of the faults with some of the musical productions. Songs were used with ridiculous fre- quency, and some were often included of such inferior qualiiy that it might have been better to have never released them. While music must have a rhythm, musical comedy is liable to be very lacking in rhythm unless the greatest care is taken The words of the dialogue must be almost as rhythmical as those of the songs, and both must fit together in a smooth pattern.
There is rhythm even in slapstick. Perhaps it is to rhythm that many favorite comedians owe their popularity. Chaplin, Lloyd, Keaton, and Langdon, all leading comedians, and all depending upon the ridiculous for their popularity, at the same time work with far more perfected rhythm than some of the stars of more serious pictures. All fully realize the value of pantomime, and of slowing up their movements when necessary. And all, while slapstick artists, know how to elimi- nate excessive action.
Some actors become stars because of their art, but some others become stars because of a type of acting which is not always art, but which the public grows to expect of them. The artist generally remains popular over a period of time, while the type actor loses popularity with unexplained sud- denness. Douglas Fairbanks, Mary Pickford, and others remain popular because they are artists as well as actors — because they act — rather than merely take directing they might not understand.
A few well done pictures mean more to the average star or featured player than a large number of mediocre ones. Of course, enough pictures must be made to supply the demand, but even so, more care can be taken with all of them. It is these pictures made to fill the general demand which have the greatest number of faults. The long-run pictures are fo- the most part of high calibre, but pictures which have but a week or so of big time are often not so great.
(Continued on Page 36)
The Capture and Photographing of Varanus Komodensis
ONE of the main problems which confronted the expedi- tion was securing permits to collect and to photo- graph the Komodo Lizard. The Dutch Government very rightly protects the lizard, which is in some danger of becom- ing extinct. It is such a curiosity that it is greatly in demand for museums and zoological gardens. To the date of writing there have never been any successful cinematographic record- ings of the lizard in natural life outside of the sixteen thousand feet which we secured.
The necessary permits being in order, a joint and co- operative expedition was formed for the trip to Flores Island, Chancellor-Stuart Field Museum and the Museum of Buiten- zorg, the latter under the capable leadership of Dr. de Jong. There were five white members in the party.
The expedition sailed from Macassar bound for Flores Island in October, 1929. The little island steamer wound through a series of small islands, and arrived at Labuan Badjo
by Philip M. Chancellor, A. S. C, F. R. C. S.
The accompanying report by Mr. Philip M. Chancellor dealing with the photographing of the almost exlinct Varanus Komodensis, is one of a series of reports which Mr. Chancellor, a member of the Ameri- can Society of Cinematographers, will present through this magazine in the coming months. The home of the Komodo Lizard is Flores Island. Mr. Chancellor secured cinematographic records of these reptiles that in years to come should prove priceless to the scientific world. — Editor's Note.
on the third day. Labuan was a small settlement whose main activity was pearling, an industry conducted by an Australian- Dutch concern. Here a few days were spent arranging for carriers and making test shots of the light, which proved to be of a very high actinic quality. We then proceeded into the mountains, the home of the lizard.
Camp was established at a small rest-house sometimes used by the Resident for deer-shooting. The "rest-house" was en- tirely a bamboo and pandanas affair with three rooms. This, however, did very well as a kitchen, store-room and labora- tory. Sleeping was all under the stars. The laboratory consisted of a roughly made table and a box, where a changing bag could be operated easily, both for loading and to make tests in a field test tank.
The natives thereabout had been informed of our coming and had selected likely spots for photographing the animals. The location proved to be a dried-up marsh, surrounded by mountains which practically formed a crater around it. A fallen
12
Mr. Chancellor in the "blind" photographing the lizards
January, 1 93 ]
AMERICAN CINEMATOCRAPHER
Thirteen
tree made an excellent camera-blind. A problem presented itself immediately. The lizards would not come out in the full sunlight on account of the heat. Oddly enough, exposure to the sun would kill them in about an hour. For this reason filming them was restricted to before eight-thirty in the morning and after five in the afternoon. The light fortunately was particularly strong and the atmosphere free of haze, — quite the reverse of Java. Some of the shots were made with the sun not quite over the rim of the hills, with the sub|ect in shadow.
In the first attempt the lizards were baited to within twelve hundred feet of the camera, but later they were brought to eight hundred feet. An Akeley camera with a MVz" f5.6 Taylor-Hobson Cooke lens was used. Most of the shots were made at f 5.6+.
It was fascinating to see the lizards feeding. The bait was a colt which had died in the village. The carcass was staked to the ground with strong lashings to prevent its being carried off. The lizard would dive in up to his shoulders, and then, lifting his head as if in challenge, would gulp down tasty pieces of meat with blood and saliva dripping from his mouth.
Certain noises would not disturb the animal. On one occa- sion when a feast was going on and there were two big fellows about, I changed four magazines and the slight click of the door did not disturb them in the least. Again by whistling in imitation of a bird to attract their attention, they would start and look about. There had been for some time a supposition that the Varanus was deaf, but evidently it was incorrect. One afternoon a squadron of four Dutch military aeroplanes
flew over, and though I could not see the planes, the drone of the motors was plainly audible to the practically unbroken silence. The two lizards that were at the time feeding also heard it and took to the hills, not to return that day. That was about the last place in the world I would expect to have the day's shooting spoiled by aeroplanes. The Varanus could run with surprising speed, though they seem far too big and sluggish to be able to move at all. They could easily outrun a man, as one was chased before the camera one day. At first he looked puzzled and a bit undecided, but when he started he exercised such force that clods of dry dirt were flying behind him.
In all, thirteen lizards were captured. These were distributed about the world in various museums, three going to Field Museum of Chicago where, at this time of writing, they are being prepared for a group.
The natives caught them by the use of a noose and small hunting dogs. The lizard would stand and attempt to fight the dogs, while some brave soul would pass the noose over its head with the aid of a bamboo pole. After that they would close in, and, grabbing him by the tail, would bind him fast to a pole to which he was securely tied. However, they were so strong that they would work loose, and on several occasions we had to get up at night to make them fast. At Labuan they were put into suitable wooden boxes and so were trans- ported to Buitenzorg where the last time I saw them they were doing well and not minding captivity, tho there is a great question as to how they will live in any foreign country. (Continued on Page 43)
£4
Two of the huge lizards photographed by Mr. Chancellor.
Noiseless Recording
Western Electric System by H. C. SILENT
Development Engineer, Electrical Research Products, Inc.
I T IS common knowledge that, when a sound print of the variable density type is played in a reproducing machine, ' the volume of the reproduction is low if the print is dark and if a compensating adjustment is not made by turning up the fader. In addition, the ground noise of the film is also low. It has been a problem to take advantage of this latter fact with the former methods of recording because the mere act of printing the sound track dark, while it reduced the ground noise, also reduced the volume of sound from the film. This, of course, was undesirable. In the method of recording which is now being employed, these undesirable effects are overcome by regulating the density of the sound track at the recorder automatically.
It is well-known that there is a particular value of density or transmission of the photographic emulsion which permits of the loudest volume from the film without exceeding the photographic limits of good quality. Deviation from this point is possible without distortion if the volume or percentage modulation applied to the film is reduced. This can be taken advantage of by causing the film to be dark on low volume modulation, and as modulation becomes higher we lighten the film to the point where it has the greatest possible carrying
capacity. If this can be done without distorting the volume of sound reproduced by the film, then we shall have a condition where the ground noise from the film is low during periods of low sound. Thus quiet intervals in the sound will be quiet and the ground noise, even though it rises with the sound, will always be more or less drowned out by the increased sound so that there is an effect of considerably reduced ground noise. In other words there is produced a constant signal to noise ratio in which the signal is always very predominant over the noise, and since noise is most noticeable in the quiet inter- vals there is a very real reduction in the amount of the ground noise.
There are a number of methods by means of which this var- iation in the transmission of the film can be effected. If we examine for a moment the light-valve employed in the West- ern Electric System of Recording, we shall see how one of these methods can be applied. In the past, this system has employed a light-valve in which two ribbons were normally spaced .001" apart. These ribbons were vibrated by the sound currents, moving but a slight distance on weak currents and a considerable distance on loud currents. The strongest currents would just bring the ribbons into contact as they vibrated. The space between them was therefore greater than necessary to
100 90 80 70 60 50 40 30 20 15 10 9 8 7 6 5 4
PER CENT TRANSMISSION
FIGURE 1
Approximate Variation of Reproduced Noise vs. Density of Sound Track.
14
January, 1 93 1
AMERICAN CINEMATOCRAPHER
Fifteen
permit the free vibration of the ribbons on weak currents. A sound track recorded under this method had a constant den- sity corresponding to the one mil spacing between the ribbons and this density was caused to vary with the voice currents but maintained always its constant average.
Under the new system of recording an auxiliary electrical circuit is associated with the light-valve, so that when the sound currents are small and the ribbons need vibrate over but a very small amplitude, they are brought close together and this small vibration almost entirely fills the space between them. Then, as the sound increases in loudness, so that the ribbons are required to vibrate with a greater amplitude, the spacing is automatically increased by the electrical circuit, so that it is always just a little more than sufficient to permit this vibration of the ribbons. This is equivalent to altering the average spacing of the ribbons, so that it is at all times proportional to the envelope of the sound currents. Now, if we regard the amount of light which passes through the average spacing of the ribbons to the film, we find that this light is considerably reduced during moments of silence or of low sounds, which results in a dark sound print. As the ribbons open up for increased sound currents, the amount of light correspondingly increases and a lighter sound print results. Since the actual vibration of the ribbons under the action of the sound currents has been undisturbed in this process, the amount of change of light which reaches the film and in turn the reproducing photoelectric cell has been unaltered even though the total amount of light has been decreased. Since the amount of change of light is unaffected, there is no volume distortion on reproduced sound as a result of this method of recording.
The extent to which the light-valve ribbons may be closed during quiet intervals is necessarily limited. They must not be completely closed, because it is not possible to construct a
device which can instantaneously sample the amplitude of the sound currents and set the ribbons to their proper spacing without introducing expensive delay circuits as auxiliary equip- ment. Therefore, in setting up the device, the spacing of the ribbons is reduced to something considerably less than their normal spacing but not as far as complete closure. Furthermore, the latitude of the photographic emulsion is not infinite and also limits the extent to which the closure of the ribbons may be effected without exceeding the straight line part of the emulsion characteristic. Since this new method contemplates recording over the same part of the film characteristic, and within the limits of this characteristic previously utilized, there is no change in film technique. The processing which produced the best quality of reproduction with the former method gives the best quality with this new method.
Referring to Fig. 1, which is an approximate characteristic of the ground noise obtained from film of various densities, the point A indicates the approximate density employed in normal recording. By shifting the ribbons to have something less than their normal spacing, we can increase the density during the quiet portions of the sound track to point B. This results, then, in a reduction of the noise in the quiet intervals. Then, as the sound currents are applied to the valve, its spacing automatically varies, so that it at all times has sufficient carry- ing capacity, as represented by the spacing between the rib- bons, to carry the applied sound currents. A slight amount of margin is always established as a factor of safety, in order that a sound which builds up suddenly will not clash the rib- bons. The manner in which the carrying capacity of the light valve or, in other words, the spacing of the ribbons varies with the applied sound currents is illustrated in Fig. 2. It will be seen from this that for weak sound currents below a certain minimum amplitude the ribbon spacing is always the minimum, and the average spacing is unvarying. As the sound currents (Continued on Page 20)
INPUT
FIGURE 2
Light Valve Carrying Capacity vs. Input.
Standardization of Photo -Electric Cells
by N. R. CAMPBELL
A Communication from the Staff of the Research Laboratories of the General Electric Company, Ltd., Wembley, England.
Courtesy of the Physical and Optical Societies, London
PHOTO-ELECTRIC cells are now regular articles of com- merce, but there is a very wide divergence in their manu- facture. There are some purposes for which every maker of photo-electric cells offers to provide cells; and yet those made by different makers for the same purpose agree in hardly a single feature. The object of these notes is to suggest that it is desirable that photo-electric cells should be standard- ized in some respects at least.
Standardization may have two objects. It may seek to fix by convention certain properties of the standardized article, or it may seek to establish some agreed system of describing its properties. The two kinds of standardization are, of course, properly applicable to different kinds of properties. The first kind is applicable to properties that do not affect materially the efficiency of the article or to those that affect it so little that the gain arising from uniformity is greater than the loss arising from standardizing any but the most efficient form. The second kind is applicable to the properties that directly deter- mine efficiency.
In the matter of photo-electric cells there is room for both these kinds of uniformity. A very large proportion of the cells sold at the present time (perhaps 90 per cent.) are used for the reproduction of talking films and for picture teleg- raphy. The efficiency of cells for these purposes is not affected very greatly by their geometrical form or by the arrangement of their terminals, while any lack of uniformity in this matter makes it impossible to substitute the cells of one maker for those of another; users of cells and, in the long run, all but the least competent makers must suffer from this lack of interchangeability. Here is a clear case for the first kind of standardization. On the other hand, the standardization in this sense of the cathode emission, which is one of the main factors determining the efficiency of the cell, would be dis- astrous to progress. Here, however, there is room for a stan- dardization of the second kind which would persuade makers to give data of the emission that they offer according to some uniform system, so that the promise of one maker may be directly compared with that of another.
Standard Cas-Fillcd Cells
Let us start with the first problem and consider, first, size and shape.
Designers of talking-film and picture-telegraphy apparatus like their cells to be small. On the other hand, there is a limit to the size of cells below which they become difficult to make and — possibly this is not exactly the same limit — below which the highest efficiency is unattainable. Maximum dimensions for cells and minimum dimensions for the appar- atus to take them should therefore be fixed, preferably in the form of the dimensions of a cylinder enveloping the cell. For the diameter of this cylinder 45 mm. may be suggested. Some existing cells have greater diameters and some existing ap- paratus smaller diameters; but this appears to be a reasonable compromise between the needs of makers and users.
The length of the cylinder will be determined in part by the terminals and by the optical arrangements. The use of a standard 4-pin valve cap for at least one of the terminals is becoming general; it should be prescribed universally, for it provides the most convenient way of supporting the cell in a fixed position. It is less certain whether both terminals should be connected to separate pins on the same cap. The objection to this plan is insufficient insulation. There is no difficulty in obtaining an insulation resistance of 10 megohms, which is
sufficient when the cell is to be used with rapidly varying lights; for then it is necessary to connect across the cell a re- sistence of not more than 1 megohm. But cells of this type, though primarily intended for use with such lights, are also suitable for other purposes, which may require an insulation re- sistance of at least 100 megohms; this is not easily attainable when both leading-in wires are brought out at the same end of the cell into the same cap. However, it may be observed that the leads, even if they are not brought out at the same end of the cell, may be connected to pins on the same cap by means of an exterior wire; this wire can be severed and separate connection made, if higher insulation is required. Ac- cordingly the question may be left to the