Paper designed to cause discussion- Effect of overspeeding on projection mechanism- Over-speeding has a tendency to aggravate the evil of oil on film- Makes picture unsteady- Has bad effect on film sprocket holes- Alters speed of motion of moving objects in screen picture and injures artistic effect- Affects the music rendition- Has one beneficial effect.
The Society of Motion-Picture Engineers, has, in its wisdom, seen fit to establish as normal speed of projection, i.e., that speed which will cause sixty feet of film to pass over the projector aperture per minute. This action presumably was founded on the presumption that "taking" (camera) speed would also be at the rate of sixty feet per minute. Presumably it was expected by the society that the projectionist would vary his speed of projection either above or below normal when it became necessary by reason of variation in "taking" (camera) speed to do so in order to produce naturalness of action of various objects in the projected picture.
Personally, the writer may and does disagree with the wisdom of adopting sixty feet as the projection speed standard, believing a somewhat higher rate of speed better calculated to synchronize with modern camera speed, and to avoid the flicker tendency which is present under modern practice which involves high screen brilliancy; but that is beside the point.
This paper is designed to set forth for your consideration those various effects which result from the over-speeding of projection, but let it be clearly understood that insofar as applied to moving objects in the screen picture, over-speeding can only be considered as taking place when projection speed is greater than was the speed of the camera which took the scene; also that the various effects hereinafter described will be of small or great in exact proportion of the variation of projection speed from normal, or, in case of screen action, from camera speed. The paper has, also, as one of its chief objects the stimulation of study and discussion of the whole subject of projection over-speeding and its effects.
Effect on the Projector Mechanism
First let us examine into the effect of over-speeding on the projector mechanism itself. We may fairly assume that the engineers who designed projection mechanisms based their calculations as to the effects of abrasions, strains and stresses that moving parts would be called upon to withstand, upon what those abrasions, strains and stresses would be at normal speed of projection, with, of course, the usual allowance for occasional temporary overload (excess speed), just as designers of electric generators base their calculations on normal load, with allowance for occasional temporary overload. It is a well-known fact that a properly designed and constructed electric dynamo will give its maximum service at normal full load, and that it will not be appreciably injured by an occasional overload, up to even as much as one hundred per cent, provided such overload does not extend over more than a brief, stated period.
Practically exactly the same thing is true of the projector. Modern projector mechanisms will give astonishingly long, efficient service when used at normal load (which in their case means normal speed) provided there be intelligent care, lubrication and proper adjustment of the tension pressure upon the film at the aperture for that speed. It is also true that the mechanism will not be materially injured, or have its working like appreciably shortened by occasional temporary excess in projection speed, even though the excess be as much as one hundred per cent.
If, however, we place an electric generator under constant heavy overload, or maintain periodic heavy overload for too long periods of time, serious damage will inevitably result, which may and most likely will very greatly shorten the life of the machine as a whole, and most certainly will work serious injury to, or even cause the complete destruction of its vital working parts.
Precisely the same thing is true of the projector. Excessive speed subjects all moving parts thereof, but more particularly the somewhat delicate high-speed parts, to a strain they were never designed or intended to withstand.
We have cited the analogy of the electric generator by reason of the fact that it is one with which we are all, we think, reasonably familiar.
The foregoing is perhaps not sufficiently detailed to be entirely convincing. We will therefore examine into the matter somewhat more minutely. At normal projection speed (sixty feet of film per minute) the projector intermittent movement acts at the rate of sixteen times per second, each time causing the delivery by the actuating cam pin, or diamond, upon the star or cross, what amounts to a sliding hammer blow, of sufficient force to start the intermittent sprocket and shaft revolving, against the inertia of the parts, plus the friction of the bearings and against the inertia of about six inches of film, plus the constantly exerted braking friction of the tension shoes upon the film, all of which is, you will realize, a not inconsiderable force to overcome, even under the very best conditions possible. Yet at normal speed this must be done at the rate of 960 times per minute, and the movement must, after being brought to maximum speed, be again slowed down to an absolute stop an equal number of times.
If we increase the projection speed to one hundred feet of film per minute this movement is increased to 27.66 per second, or 1,599.6 per minute and if we still further increase projection speed to 120 per minute it reaches the enormous total of thirty-two per second, or 1,920 per minute. Think of it! Thirty-two times per second the intermittent must start its mechanism and several inches of film, against the pull of the various forces before enumerated, from dead still bring the parts to high speed and again stop them to absolute stillness. And this must be done by comparatively light mechanism, which must be, and remain absolutely mechanically true (absolutely) in the ordinary meaning of that term. There is nothing actually "absolutely mechanically true," if it is to give a perfectly steady picture on the screen.
In considering this matters it is well to remember that the normal speed of a twelve-inch circular saw is less than two thousand revolutions per minute. The speed of the armature of electric generators, except small, high-speed generators, does not nearly reach nineteen hundred per minute. It therefore follows that at a projection speed of 120 per minute the intermittent movement is taking place at a speed greater than the normal speed of a twelve-inch circular saw, or the normal speed of the armature of the electric generator.
It should require no unusual powers of discernment to understand what the ultimate effect of such a terrific strain will be, if long continued. It cannot but result in the very great shortening of the life of the mechanism, and the rapid breaking down of its accuracy of function.
It is quite possible there are those who do not realize the frequency with which over-speeding is practiced in theatres. For their benefit I will say that hundreds upon hundreds of theatres, or socalled theatres at least, make it their regular practice to project a thousand feet of film in as little as eight minutes. Other hundreds do the same thing at certain "rush hours" of the day, either every day or on certain days of the week. Eight minutes to the thousand feet of film is at the rate of one hundred and twenty-five feet per minute. It is a deplorable fact that even some large, otherwise high-class theatres make it their habitual practice to project at the rate of from ninety to a hundred feet per minute.
The resultant damage to film and machinery is directly in proportion to four things, viz.:
(A) The amount of excess speed. (B) Amount of braking power the tension shoes exert on the film. (C) Condition of the mechanism and (D) Lubrication of the Mechanism.
It is a well-established fact that the exhibitor who abuses his projectors by over-speeding, almost invariably blames their consequent shortness of life and the excessive repair bills upon faulty construction of the projector itself, instead of upon the abuse to which he has caused it to be subjected.
Oily Film Traceable, In Part, To Over-Speeding
Another evil the motion-picture industry is called upon to bear which, while not entirely due to over-speeding, is nevertheless greatly augmented thereby, is oil on the films. If we examine the films in any exchange we will be reasonably certain to find seventy-five per cent of them carrying oil to some extent. A goodly share of this percentage, will carry considerable oil, while some films will be literally smeared with it.
This state of affairs is traceable to several causes, but it is a condition always greatly aggravated by over-speeding, partly because of the natural inclination to over-oil a mechanism which is working under heavy stress, and partly by reason that as speed of rotation of revolving parts increases there is added tendency to throw off oil by centrifugal force, and much of which finds its way, eventually, to the film.
Unsteadiness of the Picture
Is always greatly aggravated by any considerable excess in projection speed above normal. This is due to several causes. First, there is the rapid wear of mechanism parts, which very naturally makes for lost motion and unsteadiness of the picture. Second, there is increased tendency to wear off intermittent sprocket teeth, due to added strain of excessively tight tension required for high speed, and worn intermittent sprocket teeth always make for unsteadiness in the picture. Third, there is the added tendency to jump when a badly made splice hits the upper end of the tension shoes. In addition to this there is, to some extent, additional vibration of the machine as a whole, which of course to some extent make for unsteadiness of the picture on the screen.
I feel there is no need to further elaborate on this phase of the subject. It should, it seems to me, require no argument to convince even the most skeptical that excess in projection speed makes for unsteadiness of the picture on the screen, nor can the fact that it is possible to project a steady picture at high speed be accepted as proof or even as evidence to the contrary.
Effect of Over-Speeding Upon the Film
One of the important functions of the projectionist is to see to it that the tension springs exert just sufficient pressure upon the film to accomplish the purpose for which they are intended. But the amount of pressure (tension) necessary to stop the film after the intermittent sprocket has ceased to act and to hold the parts in retard, will depend in large degree upon the speed of projection, since the braking action of tension shoes upon the film has entirely to do with overcoming the momentum of the film and holding the intermittent sprocket in retard when the movement ceases to function. It therefore follows that decidedly less tension will be required at normal speed than at high speed, and that, always assuming the tension to be adjusted to the actual requirement, the strain upon the film sprocket holes, the teeth of the intermittent sprocket and the whole intermittent movement as well as the various gears of the mechanism will be greatly increased by increased speed of projection; also that the added tension made necessary by increased projection speed will produce abnormal wear upon the aperture plate tracks, as well as aggragate any tendency of emulsion to deposit upon the tension shoes, and to increase the tendency of such deposit to do serious damage to the film.
In connection with the foregoing we must call attention to the fact that by proper construction it is possible to so support the film in its path between the upper end of the film gate and the intermittent sprocket that the film itself will in some measure act to reduce the amount of tension necessary; also that closeness of intermittent sprocket to aperture, and the holding of the film in firm contact with the intermittent sprocket has some bearing on the amount of aperture tension necessary for a given speed.
Before closing this phase of the subject let me cite, in proof of the strain under which the intermittent mechanism of a projector and the edges of film sprocket holes work, the following facts.
So great is the pull of the film upon the intermittent sprocket teeth that even though the teeth be of the finest grade of steel and hardened as much as possible, still the film cuts or wears away the metal in a comparatively short time. In considering this fact as applied to the total amount of pull exerted upon the film, as against its almost negligible inertia plus the braking power exerted by the tension springs, let it be remembered that there are eight of the intermittent sprocket teeth contacting with sprocket hole edges at all times. I think you will agree with me that when the pull is so great that glass-hard steel is cut away from eight teeth at the same time, and the cutting is done by a celluloid sprocket hole edge six one-thousandths of an inch in thickness, and that those sprocket hole edges are contained in a film having considerable money value, the reducing of the pull on the intermittent sprocket teeth to its lowest possible value is an important item, while increasing it needlessly is a very serious matter indeed; that overspeeding does increase it, always presuming to be reduced to its necessary value for normal speed, cannot, I think, be seriously questioned, though, as before remarked, there may be a less percentage of increased tension pressure for a given increase in projection speed in a mechanism in which the film is well supported in its passage through the film gate, and where the distance from intermittent sprocket to aperture is short. Such claim is made, and it seems reasonable, though the author has made no actual test of the matter.
Summed down, we find that with normal projection speed as against over-speeded projection, there is decidedly less wear of the projection mechanism, intermittent sprocket teeth, film sprocket hole edges, aperture plate tracks, and tension shoes, as well as less tendency for deposit of emulsion on the tension shoes, and less liability of such deposit to do serious damage to the film. We find also that wear of intermittent movement, gears, bearings and intermittent sprocket holes and sprocket hole edges increases very rapidly with increase in projection speed, as also does tendency to over-oil and the throwing off of oil from moving parts.
Just what the actual damage due to over-speeding projection as expressed in dollars and cents, it is impossible to say, for the reason that no reliable figures are available as to the actual number of feet of film in daily use, the average value per reel of the film in daily use, or the average percentage of damage done to each reel. The writer has himself placed the probable number of reels in daily use in the United States and Canada at 120,000, but the actual figure may be either more or less. From long and intimate association with matters pertaining to projection we believe we are able to form what may be termed a reasonably intelligent idea of such matters. If we accept the number of photoplay theatres in the United States and Canada (16,000) as approximately correct, and assume the average daily program to consist of seven reels, we then have a total of 112,000 reels of film in daily use. If we then, taking new and old together, estimate the average money value of these reels of film at $50.00 cash we will have a total of $5,600,000 as the cash valuation of film in daily use in theatres of the United States and Canada. These figures, while admittedly somewhat in the nature of a guess, will, we believe, err, if at all on the side of conservatism. However, in order to be entirely safe, let us arbitrarily subtract from the total the sum of $2,000,000 leaving $3,600,000 as the actual cash value. With these figures before us it requires but a glance to see that, even with the above ultra-conservative estimate of valuation, any considerable percentage of unnecessary damage to film is a very serious matter indeed. Even so infinitesimal an amount (in percentage) as one-tenth of one per cent. of unnecessary damage would reach the respectable sum of $3,600. The personal opinion of the author is that unnecessary damage to film traceable wholly to overspeeding will reach the least one-fourth of one per cent per day, and one-fourth of one per cent is, based on the above estimate of valuation, $9,000. Bear in mind the fact that any damage done to film or to machinery must inevitably be absorbed in the "overhead" of the industry, and that part having to do with film ultimately be charged back to the exhibitor in the form of increased film rental, because in the last analysis every item of expense incurred by the industry, no matter what its form, must be paid for out of boxoffice receipts, since the industry has no other source of income. Please understand that in the foregoing estimate of probable damage we firmly believe ourselves to have been ultra-conservative- that the actual figure is very much in excess of that named.
In addition to the foregoing we must not overlook the fact that there are not less than 25,000 projectors (probably a substantially larger number) in use in theatres of the United States and Canada. These machines probably cost exhibitors an average of not less than $400 each, or a total of $10,000,000, and if their average life be shortened through abuse in over-speeding by as much as ten per cent., it will be seen that additional serious overhead expense is incurred by the industry, since 10% of $10,000,000 is $1,000,000.
It will, of course, be understood that the values quoted are arbitrary. They are based merely on what the writer believes to be probable after many years devoted to the study of projection practice. The actual amount of damage may be either more or less. But that damage of considerable amount results to both film and projection machinery through over-speeding will be generally admitted by every one in the least conversant with projection practice I have no doubt. The main intent of this paper is to call attention to the matter in a way which will cause further investigation, rather than to quote exact values of damage actually done to film and machinery.
What Happens to the Music
Another effect of over-speeding projection is to speed up the music, and thus very often ruin its artistic effect. This, however, acts, both ways, because as a matter of fact, unless there be very careful selection of music which will synchronize with projection, it may be found that the projection of some scenes at normal speed will act to slow down the music and thus injure, if not ruin its effect. In the foregoing we assume that there is a certain definite relation between tempo of music rendition and tempo of screen action, and that in most instances the two must agree unless one or the other is to suffer.
Injury to Screen Action
But, after all, by far the greater damage due to over-speeding projection is found in the injury to the action of the photoplay itself. This one thing has, we venture the assertion, done more to render difficult the popularization of the photoplay as a high-class form of theatrical entertainment than any or all other causes combined. It has tended to cheapen the photoplay and to prevent its drawing at high prices, except where some story of extraordinary power, supplemented by wonderful scenic effects, has offset the unnaturalness caused by high speed, or where the screen has been supplemented by added attraction.
The industry pays literally high sums to individuals to enact the principal roles in photodrama. This is by reason of the fact that these "stars" have established a "drawing power." In examining into what constitutes this drawing power we are certainly justified in assuming its main foundation to the ability to portray the character artistically. Who will dispute this? And if that be the fact, then does it not follow that their rendition could hardly be improved upon by so ordinary a person as a theatre manager or a projectionist, or even by the producer himself? That much is hardly subject to argument. It may be accepted as fact; and if it is fact, then it naturally follows that the artistic rendition for which huge sums were paid to the artist may only be reproduced on the screen when projection is at precisely the speed at which the camera "took" each individual. scene. That, too, is fact, is it not? If the tempo of projection be speeded in any degree above speed of "taking," the effect, insofar as relates to moving objects on the screen, is altered, and the alteration is in exact proportion to the excess of projection speed over "taking" speed.
If the actor enacted a death-bed scene artistically, which was photographed at sixty per minute, and same scene be projected at ninety, the action of the artist is changed into quick, jerky movements which convey to the audience an entirely different impression than would have been conveyed had the scene been projected at taking speed. The death-bed scene is still a death-bed scene, true, but into it has been injected an element of the ludicrous, which has the effect of intermixing its solemnity with farce comedy. "Pep" is all very well and highly commendable in its place, but, when pallbearers are made to come out of the house at something between a trot and a lock-step gallop and to dump the coffin into the hearse with a zip, we believe the "pep" thus displayed is misplaced. Certainly the screen gains nothing by such an absurd speeding up of its action.
It must be noted, however, that there are occasional exceptions where a scene may actually be improved by moderate overspeeding of projection. Such scenes are, however, rare. As a rule they are those where speeding automobiles are involved, with no animate figures other than those in the machines. Such scenes merely form the exception which proves the rule.
In over-speeded projection the film story may carry itself, but it is nevertheless an unnatural, weird and ofttimes entirely absurd performance, which is anything else under Heaven than satisfactory. It gives the effect of unrealness, thus keeping constantly in the subconscious mind of the audience the thought that it is looking at a mere picture, whereas with action at normal speed, with attendant naturalness, it is not at all unusual for the audience to become sufficiently lost in the action to forget the screen and actually live in and with the play.
The author ventures the assertion that over-speeding of projection, as applied to its effect in the alteration of action of moving things on the screen, with resultant effects on the minds of photoplay theatre patrons, is the one worst enemy with which the industry has to contend.
It is not within the province of this paper, which is already too long, though there is ample material for many more pages, to enter into detail as to the causes of over-speeding. They are many, but chief among them is the desire of theatre managers to "run to schedule," which means the allotting to each show a certain number of minutes, regardless of variation in film footage or musical or vaudeville numbers, and the desire to crowd into those minutes a program which can not be properly handled in the allotted time. The average theatre manager seems to consider a reel of film as standing for a certain number of minutes of show. This would be entirely true if
(b) All cameramen photographed all scenes at precisely the same length;
The One Single Beneficial Effect of Over-Speeding
Is found in the fact that it tends to reduce or eliminate any flicker tendency there may be at normal speed.
F.H. Richardson, "The Various Effects of Over-Speeding Projection," Transactions of S.M.P.E., No. 10, meeting of May 9-11, 1920.
© 1998, David Pierce, on editing and revisions (if any)
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