FIGURE 43.
A form of intermittent movement which has lately come out and is used on the Powers No. 6 Cameragraph is shown in Figures 40 to 42 inclusive. The moving element of this intermittent movement is a diamond-shaped projection on the surface of a revolving disk. The driven element is a cross carrying four pins—termed a “pin cross”—and is indicated by broken lines. The raised portion A of the diamond strikes one of the pins of the cross and starts it in motion as indicated in Figure 41. The movement of the cross can be traced by the black dot indicating one of the pins. At every revolution of the driving disk, the cross makes one quarter of a revolution and when not in motion is held rigidly locked by the locking ring R, which fits snugly between the pins. This movement probably moves the film in the shortest time of any. It is entirely encased, runs in oil, and is practically noiseless. The manner in which it is installed in the machine is indicated in Figure 43.
M—Lower Feed Loop.—The lower feed loop is provided to prevent the lower sprocket from pulling on the film and thus interfering with the work of the intermittent sprocket. The intermittent sprocket feeds the loop, by jerks, three-fourths of an inch of the film at a time; and the lower sprocket is geared to take away that much by steady motion. Thus, everything working properly, the loop remains of the same size. In case the lower sprocket is not working properly, the loop may become enlarged and the film may run onto the floor. Sometimes the intermittent sprocket does not work properly and the lower sprocket pulls away all of the loop.
N—Lower Steady-Feed Sprocket.—The lower steady-feed sprocket maintains the loop and restrains the film. If it were not for this sprocket, the take-up mechanism would pull directly on the intermittent sprocket and keep the film jiggling.
FIGURE 44.
O—Take-up Reel.—The take-up reel is identical with the upper reel and, in fact, the two are generally used interchangeably. In both cases, only perfect reels should be used; and reels delivered by exchanges are very often untrustworthy.
The principle of the take-up mechanism is shown in Figure 44. When a run of film is started, the diameter of the roll of film being small, the reel must travel comparatively fast to take up the film as fast as it is unwound from the upper reel. As more and more film is gathered by the lower reel, the travel must become slower until finally, with a twelve-inch reel, the number of revolutions per minute are but about one-fourth as many as at the beginning.
In Figure 44, A is the reel which is fastened to the spindle B; C is a collar also fastened to the same spindle. D is a loose pulley capable of revolving around the spindle without imparting motion to it and arranged so that it can be driven by a belt. E is a spiral spring which is controlled by the small collar F, and it presses the loose pulley against the collar C. If the loose pulley is pressed against C with sufficient force, it will cause C to revolve with it; and the movement of C will impart motion to the reel and wind up the film which is fastened to it. D must revolve fast enough so that, even when the reel is empty, it will take up all of the film fed to it. As the film is wound up, the size of the roll of film increases and the speed must become less; thus D begins to slip a little on C and this slippage increases until the end of the run.
Friction in one form or another is the only method by which take-up reels are now operated; but in some of them this friction may be in a belt, as well as in the two disks as shown. Sometimes a fiber washer is interposed between the two friction disks. In the Motiograph take-up, Figure 45, the necessary friction and slip are all in the belting.
FIGURE 45.
If the take-up is not handling the film properly, it is due to a loose belt or to insufficient tension on the spring. The take-up probably causes more trouble than any other part of the mechanism and it should be carefully watched. On account of the trouble incurred from it, there are still many operators who prefer to run films into a tank; although the take-up saves them much time. A careful operator who understands the care of machinery would have little trouble with a take-up; while the one who has not the faculty of keeping things in order would, perhaps, be better off (fire hazard neglected) with a tank. With most machines, the take-up magazine is located where it is very difficult for the operator to watch its operation. Those machines in which it is located in easy sight of the operator have considerable advantage in this respect. A careless operator is often compelled to open the lower magazine door and turn the reel by hand when the take-up tension is out of order. Remember that the take-up can cause trouble only when it is out of order and that a good operator will never allow it to get out of order and he will inspect it carefully before every show.
P—Framing Device.—The aperture in the film gate is just large enough to fit the picture on the film. If the film is accurately placed, the whole picture will show upon the screen. In order to bring this about, the machine must either be provided with a means of adjustment, or a certain part of the film must be placed upon a certain sprocket tooth. This latter method causes considerable annoyance and waste of time; furthermore, every splice in a film would have to be made exactly right or the whole succeeding part of the show would be “out of frame”. In order to avoid these troubles, every machine is provided with a so-called framing device. Somewhere about the machine, convenient to the operator, will be found a lever by which, during the operation of the machine and without interruption, the position of the film with reference to the film window and the lens may be adjusted either up or down. The precise manner in which this is done varies with different machines. The framing device must be capable of adjusting the film to somewhat more than the width of one picture.
The splice should be so made that framing becomes unnecessary and this is accomplished by cutting out full pictures so as to leave each picture with the full four holes. If a picture is left, for instance, with only two holes, it will appear upon the screen with the black line, which should be hidden in the center. If this happens, by moving the framing lever either up or down, the picture can again be centered upon the screen.
FIGURE 46.
Q—Film Shields.—The film shield is an important part of the machine; although it is often very much neglected and in many machines is so small as to be practically useless. It should prevent films from crowding out into the light when the loops enlarge. Many operators do not take kindly to machines that enclose the film too tightly; for in case the take-up fails to work properly, it is often a convenience to be able to handle the film. This is also the case where very badly torn or old film is used. Many old films are so badly worn that they will not run properly on the sprockets and must be very closely watched.
FIGURE 47.
FIGURE 48.
It is not thought necessary or advisable to go into the details of construction of any particular machine as changes are made nearly every year so that such description would not be of great value and might, in fact, be misleading. Any person possessing a little mechanical ingenuity and taking an interest in such matters can readily learn the peculiarities of any of the machines. They are, after all, when one has mastered the principles, quite simple affairs. All progressive manufacturers, furthermore, publish instruction books which are issued whenever a change is made in any machine; and these are always obtainable.
FIGURE 49.
In Figure 46 we have a general view of the Edengraph machine. It will be noticed that the total length of film between the two magazines is exposed to view making threading of the film very easy; also that the revolving shutter works between the objective lens and the film gate.
The well-known Edison machine is shown in Figure 47. This is one of the best known machines; and it is very compact and durable.
FIGURE 50.
The Motiograph is shown in Figure 48. The take-up, shown on the lower magazine, is different in this machine from what it is in the others. This machine also has a special rewind feature. By an adjustment of the operating handle, the film, after having been run off onto the take-up reel, can be rewound upon the upper reel without taking it out of the magazines.
Figure 49 shows a general view of the Powers No. 6 Cameragraph mechanism.
The Simplex mechanism is shown in Figure 50. In this machine the film is entirely enclosed between the two magazines.
Film Making and Characteristics.—All film is of celluloid. The commercial film used for the projection of motion pictures comes in long strips, is about one and three-eighths inches wide, and about one two-hundredths of an inch thick. Upon one side of this film is a photographic emulsion of gelatine impregnated with a solution of bromide of silver. This silver is sensitive to the light and has the property of turning black, during the process of developing, in proportion to the quantity of light that has struck the different parts of the emulsion. Wherever the light has been very intense or has been applied for a sufficiently long time, the film, after treatment with a proper developing fluid, becomes very black; where no light has reached it, it remains white; and in the intermediate portions, the shading is in proportion to the light that has reached those parts.
Film that has not been exposed and developed is of a creamy yellowish color and, if immersed in a solution of hyposulphite of soda, will turn perfectly clear and offer no obstruction to the light. If, on the other hand, it is completely exposed and developed, it will become solid black; such black pieces are sometimes used as leaders and tails in connection with motion pictures.
The emulsion on the film melts at a temperature of about 90 degrees Fahrenheit and will then run off the film. It is also soluble in warm water. The celluloid of the film is very inflammable and bursts into flame at a temperature of 284 degrees Fahrenheit. If it is ignited while tightly wound upon a reel, it burns somewhat slowly; if it is ignited in a tank, the beginning of the fire is also slow; but as soon as the air in the tank attains the proper temperature, the whole of the film bursts into flame at once. It acts in this respect very much like gunpowder. In burning, the film gives off a dense brownish mass of poisonous smoke. Film will burn even when it has no access to the air and a film fire cannot be put out by smothering.
Before sending out their films, the manufacturers treat them with glycerine. This is for the purpose of keeping them pliable as long as possible. In time, however, a film dries out and there is then very little that can be done with it. At any rate, whatever is to be done should be done by the exchange, as no operator has facilities for handling it.
Some films are waterproofed and a little water will not damage them much; but other films must be kept dry. If by accident a roll of film should become wet, it can be saved by very quickly unrolling it and spreading it out to dry. If it can be spread out quickly enough, it will not be harmed; but if it is not spread out at once, the emulsion will stick to the celluloid and will come off when the film is finally unwound.
There is also a process of fireproofing film. This must not, however, be too thoroughly relied upon, especially if the film is old. Fireproof film is a valuable aid, but it is best to treat it exactly like other film in respect to the fire hazard.
On account of its inflammable character, film should always be kept in fireproof enclosures.
The film contains sixteen pictures to each foot and for every picture there are four sprocket holes on each side of the film. The size of the aperture plate and also the size of the actual picture on the film is 11⁄16 inch high by 15⁄16 inch wide. If the picture on the screen is enlarged to 18 feet 9 inches in width and 13 feet 9 inches high, every part of the picture on the film will appear 57,600 times as large on the screen as it is in the film. In viewing a 1000-foot film, the audience will see 16,000 separate pictures following each other so rapidly that the change from one to the other will be unnoticeable. If a three-blade shutter is used, the beholder will see the light shut off and turned on 48,000 times in the same run of film, but will not be able to notice it if the speed with which it is done is correct.
New film coming directly from the exchange is likely to be too moist and cause trouble from that condition; while old film is likely to be too dry and cause trouble by warping or bending out of shape.
Patching Film.—All reels of films contain patches and but little trouble will arise from them, provided they are properly made and reasonable care is exercised in watching them. In order to obtain a satisfactory splice, it should not be made more than 3⁄16 inch long; a greater length than this will reach two sprocket teeth and this is objectionable because the splice stiffens the film and will prevent it from fitting the teeth properly. The splice should be so made that it does not throw the pictures out of frame. If made properly, it will never be noticed in the running picture at all, unless a large quantity of film is cut out. If however, the splice be made over part of a picture—as would be the case if an improper number of holes were cut out—the picture, when projected, would appear out of frame, i.e., the dividing line between two pictures would then appear on the screen and would continue to show until the framing lever had been adjusted to cover the dividing lines again. Care must also be taken that the film is straight after being spliced. If the ends are not fitted squarely to each other, there will be a bend in the film at the point the splice is made; and this may cause trouble.
Many operators have a plate of ground glass fitted into a work bench at the place where splices are to be made and a small lamp under this glass. This is very convenient for, as a rule, the illumination in an operating room is very poor although a good light is necessary to match film properly. If ground glass is used, the rough side must be at the bottom; otherwise it will be difficult to clean off the cement which adheres to the glass.
By making every splice in exactly the same order, the operator will acquire the habit of doing it nicely and quickly. Most splices are made in a hurry (before or after a show) and in this, as well as in all things that must be done hastily and at a moment’s notice, habit and practice are very important. One does not become expert until he has practiced it often enough to be able to do it mechanically.
FIGURE 51.
Proceed as follows and as outlined in Figure 51: Cut exactly along the dividing line of one picture and save this to become the top piece. (The emulsion side of the two sections of film must always be either up or down, and for convenience it is well to form the habit of having them always one way or the other.) Now, with a sharp knife, scrape the celluloid side of this piece until all of the gloss is removed for a width of a little more than 3⁄16 inch. Do not scrape any more than necessary, but be sure that all dirt and oil are removed. Now take up the other part of the film and cut off the bad portion, leaving a strip a trifle less than 3⁄16 inch beyond the dividing line. This strip need not be scraped on the back, but all of the emulsion must be scraped from the front side of it. To scrape the front side nicely, lay a short ruler across it to act as a guide for the knife and scrape up to this ruler. Scrape only to the dividing line, but give particular attention to the sprocket holes and the edges, for it is at the edges and sprocket holes that film first begins to work loose and where it is most difficult to secure proper adhesion. Both parts of the film should be so scraped that, when finished, each will furnish half of the dividing line. Now apply a liberal coating of cement to the latter section and carefully lay the first upon it, taking great care that the sprocket holes in the two sections overlap and match perfectly. It is for this matching purpose that the glass in the table (with a small lamp underneath it) is valuable. The sprocket holes must match accurately and the films must line up straight. After the upper film is placed, it must be pressed down for a few seconds until the cement has set. Wipe off all superfluous cement before it has time to set. Be sure that there are four sprocket holes for each picture. Keep a knife on hand and use it for no other purpose. Keep also a suitable stone on which to sharpen this knife, for, unless the knife is very sharp, it will do only poor work and the edge on it will not last long at any rate. Ordinary cement will not hold non-inflammable film, and water-proof film must be more thoroughly scraped than ordinary film. In the bench, provide a recess into which the cement vessel may be set and where it will always remain. Provide also a pair of scissors for cutting the film.
FIGURE 52.
The Edison film mender is shown in Figure 52. This is made with three gates or hinges. Those on the right and left clamp down to hold the film, while the narrower one in the center clamps down on the cemented edge. To mend a film, place one of the pieces to be joined in the mender. Place that part of the gage marked “cut” in position, cutting between first and second perforations above the floor line separating the picture. The remaining piece of film should be placed in the other side of the mender and cut exactly on the line. Set the opposite end of the gage marked “scrape” on the first section; remove the emulsion; cut to the floor line with a sharp pen knife, moistening it so that the emulsion will come off easily. After applying the cement with a brush to the scraped piece, lay the other piece over it in the mender, clamping it down; and leave it for an instant to adhere.
Tools.—First of all provide a suitable and sufficient set of tools. There should be an assortment of screw drivers, large and small, to fit the different sizes of screws used not only with the machine but about the operating room and with other devices as well. Keep these screw drivers filed or ground to proper shapes. A screw driver rounded off, or too small, or bent, will ruin the heads of the screws. There should also be a collection of pliers (especially such as are commonly termed “gas pliers”), files, raps, chisels (for wood and metal), punchers, drills, and monkey wrenches; a hack saw, a blow torch, and a vise will also come in handy. Tools, however, depend upon the man who uses them. There are men who would be no better off with such a collection at their disposal; on the other hand, a clever man would be able to make use of all these tools and show his skill thereby.
Aligning the Machine.—The first thing to do in setting up a new machine, after it has been unpacked and put together, is to line it up properly. This can be done by stretching a string from the lamp house, through the center of the condenser opening, film gate, and objective lenses. These must all be in such a position relative to one another that a taut string will pass through the center of each. The center can be determined by measurement either with a suitable rule or a pair of calipers.
Anchoring the Machine.—The next step is to anchor the machine so as to reduce vibration to a minimum. Vibration is often due to a flimsy floor which will not stand the strain of the unavoidable vibration and thus helps to increase it. Often, however, the vibration is due to some part of the running gear of the machine, such as the revolving shutter, for instance, being out of balance. If there is undue vibration, the machinery should be looked after first, for it is much better to prevent the vibration by removing the cause than to seek to restrain it by bolts and braces. If the machine runs very badly, it cannot be bolted down with any satisfactory results.
Inspection.—After the machine is lined up and running smoothly, the next step should be to inspect every part of it thoroughly for loose screws, pins, gears, or other parts. It is best to do this by beginning at one end and continuing to the other so that no part may be overlooked.
Upper Magazine.—See that the spring in the upper magazine, or on the door of it, which prevents the momentum of the upper reel from running off film after the sprocket has ceased pulling, is in good order and the reel true. A crooked reel will generally cause trouble and force the operator to keep the magazine door open so as to be able to aid the movement of the film.
Fire Trap.—The fire trap must next be looked after. The upper magazine, the fire trap, and the sprockets must all be in perfect alignment and the film must run through the trap without touching either side. Film wears the metal very fast and a day’s run with the film brushing one side of a valve will show decided wear. If it is allowed to run this way, it will soon cut through the side of the valve, forming an opening in which the film will run and in which it will often catch and tear splices. Special care must be exercised to see that the traps are kept clean and, when not in use, they should always be covered. The film is drawn through the traps very rapidly and any kind of dirt accumulating on them is apt to scratch it. After a fire, burned film is likely to be found in the trap, and this, when cold, becomes hard and is difficult to remove.
Cleaning Machine.—After the machine has been used for a considerable time, it is advisable to wash out the gears thoroughly. Not only the gearing, but the bearings also, should be reached by this process. If one has plenty of gasoline and a suitable receptacle, the quickest way is to take out the lenses and immerse the whole machine for a while in a vessel filled with gasoline. It can then be taken out, worked a little, and immersed again; this process being repeated until all of the old and hardened grease is worked out. If facilities for immersing the machine are not at hand, the bearings may easily be cleaned by using kerosene or gasoline to oil them and then running the machine a little; this will work all of the old grease out of the bearings. The gearing can be cleaned in the same way. If gasoline is used, it will quickly evaporate and leave the machine in good order.
Oiling Machine.—After the machine is thoroughly cleaned, it may be oiled again. The best lubricants to be used range all the way from sewing-machine oil to beeswax. Beeswax is used only for the gearing and only where that is somewhat worn. It is solid enough to compensate for some of the wear. That part of it which works out on the sides should be wiped off at once. There are many lubricants to be recommended; in general, however, the particular kind to be chosen depends upon the parts to be lubricated. A part moving rapidly with no great friction can be well served with a light lubricant, but heavier parts, or parts that fit so closely as to cause much friction are best served by some lubricant that has more body. If a light oil is used, it will of course have to be applied oftener than a heavy oil. None of the extremely light oils should be used because they run off too fast.
Care of Sprockets.—Having thus cleaned and oiled the machine, the next step is to look after the sprockets. In an old machine it is likely that the sprocket teeth will be so worn as somewhat to resemble hooks. A little wear of this kind will do no great harm, but beyond a certain point of wear, the sprocket teeth tend to carry the film farther than is necessary and in so doing tear out the holes. Some sprockets are made reversible and the trouble can be remedied by turning the sprocket wheel around. In most cases it will, however, be advisable, when the old teeth are badly worn, to get a new set of sprockets.
The sprockets must also be examined for accumulation of dirt, for in case there is much dirt on a sprocket, it will not guide the film properly. The dirt will cause it to jump, and thus bring about an unsteady picture; or, if the accumulation of dirt is sufficient, it may even cause the film to jump off the sprocket. Hundreds of feet of film have been ruined in this way. The sprockets should be cleaned every day with a suitable brush. An operator too careless to clean his machine properly, is also as a rule too careless to watch the picture properly; and he suddenly finds himself with a length of film ruined by sprocket teeth which have cut a row of holes through the center of it.
The sprocket should be made to align perfectly with the upper and lower magazines, the fire valves, the film gate, and the path of the film. They may be aligned with a straight edge made of a flexible piece of steel or, if nothing else is available, a piece of film may be placed upon the sprockets. Be sure to examine the film carefully before using it for this purpose; old film is apt to be warped. The film must fit perfectly in the aperture and on the different sprockets. The sprockets must have little or no end play, especially the intermittent, or it may cause the picture to wiggle sideways. The idlers, or presser rollers, should not fit tight enough to bind, but must fit closely enough to hold the film securely. In the adjustment of these and all other parts of a moving picture machine, considerable practice and judgment are necessary to estimate how much freedom of movement is permissible.
Adjusting Intermittent Sprocket.—The “Geneva” wears rapidly when it is not well oiled or protected; and it becomes necessary to adjust it. There are other ways of doing this but generally it is done by means of an eccentric bushing which must be set to compensate for the wear. In many operating rooms, there is a wide range of temperature and, as heat expands the metals, they will bind unduly when they become warmed up, if the star and cam wheel are set too close while cold. In many machines the heat from the lamp warms them up irrespective of the temperature in the operating room.
Automatic Fire Shutter.—Some means of adjusting and regulating the automatic fire shutter is usually provided; this should be adjusted so that it will not rise before the machine is in motion and will fall before it has come to rest. Under no conditions should the stationary film be allowed in the path of the light. There are fire shutters that do not depend upon the motion of the machine, but are raised as soon as the handle is pressed to give motion to the machine. This type of shutter is raised as soon as the handle is pressed and may expose the stationary film to the light. Such a shutter should not be tolerated at all. The fire shutter should be carefully tested to see that it operates properly under all conditions. If one is not acquainted with the particular type of fire shutter in use, it is advisable for him to test it with the lamp turned on it for some time. Some shutters are so thin and are placed so close to the film they are supposed to protect, that it is possible to fire the film through them.
The Revolving Shutter.—In some machines the light is shut off before the film begins to move, and in others a very slight movement of the film is permitted before the shutter closes out the light entirely. The general object of the shutter is to shut off the light while the film is moving and to interrupt the long period of light so that it may not affect the eye too strongly and give rise to the sensation of flicker. The exact manner of setting the shutter varies with different machines, but in general the above consideration must be kept in view. Where a shutter has several blades, it is always the larger one that shuts off the light while the film is moving and this is the only one to which any attention must be paid while setting.
The best test for the setting of the shutter is the appearance of the picture. The best kind of picture with which to judge a shutter is one that has strong contrasts of light and darkness. If a picture contains a very bright object, the travel ghost will appear if there is any motion while the light is on the film. If the shutter is set too late, the travel ghost will be in the lower part of the screen; and if too soon, in the upper. If the shutter is made too small, the travel ghost cannot be entirely eliminated but must be divided half on the lower and half on the upper side of the picture. The travel ghost and other imperfections of a picture are much more noticeable to persons close to the screen than to those far away. As the operator himself is the farthest away of all spectators, he is likely to miss many imperfections that are plainly visible to the audience. For this reason many operators have opera glasses through which they view their pictures.
Framing.—When the machine is finally threaded, the film should be so placed on the upper sprocket that, with a proper loop, the picture will be in frame when the framing lever is about in the middle position. This position will allow the operator to frame either up or down without seriously affecting the loop. The framing is best done by looking at the picture thrown upon the screen.
Film Gate.—The film gate needs special attention when new film is being used. Very often new film is so damp that some of the emulsion sticks to the gate. Wet film running through a machine makes it work hard and is likely to cause much trouble. With such film it is often necessary to stop during a run and clean off the gate and it is always necessary to do so after each run. Never use a sharp tool or anything that may scratch the gate or roughen the bearing surfaces where the film runs. The gate must be watched closely for wear; if worn too much, the picture may be out of focus or jump in all directions.
Tension Springs.—The tension springs will repay careful study by the operator. The object of the springs is twofold: First, to hold the film flat, and second, to introduce sufficient friction to overcome quickly the slight momentum which the film has acquired while in motion. The springs should be just tight enough to do this. The pressure of the springs necessary to overcome the momentum of the film is proportional to the speed at which the film moves. If the film is to be run at a high rate of speed—as is often the case when a crowd is waiting outside the doors—the tension must be increased, unless it was originally great enough to hold the film at this rate of speed.
As the film varies in thickness, the adjustment cannot be made too close; but the springs must be made tight enough so that they will hold the film at the highest rate of speed when the thinnest part of the film is passing through. If the springs are not sufficiently tight, the picture will seem to move a trifle. They must be just tight enough to prevent this at the highest rate of speed at which the machine is to operate.
The Take-Up.—The lower sprocket exists for the purpose of restraining the take-up from pulling on the intermittent sprocket. There is thus actually always a strain that the one puts on the other. For this reason the tension on the take-up should be no greater than necessary. Excessive tension will increase the wear on the machine; may cause the tearing of many splices; and will cause the machine to run hard, thus imposing extra labor on the operator. While the lower reel is nearly empty, the strain is small; but as it fills up, the strain becomes greater. The driving wheel or belt must move at a fixed rate of speed while the slip of the driven wheel becomes greater with every turn. Thus the energy expended in friction becomes greater as the picture progresses. Defective belting, crooked reels, or poor adjustment of tension are the most frequent cause of annoyance in the take-up and the take-up as a whole gives probably more trouble than any other part of the equipment.
Cover.—Every machine should be covered when not in use and the cover should be dust tight.
Getting Ready for the Show.—The first thing for the operator to do before entering the operating room is to put away all smoking paraphernalia he may have about him. No smoking tobacco or matches should ever be found inside of any operating room. After taking this precaution the next thing will be to rewind and inspect the films to be used for the next performance. If the reel happens to be properly wound when received, it is not absolutely necessary to rewind it and, in an emergency, one may take a chance and run it through without previous inspection. When possible, however, the operator should always inspect his film before using and also familiarize himself with its contents.
A film is best inspected by rewinding it slowly from one reel onto another, gripping it with a gentle pressure, and allowing it to run between the fingers. This method will catch all splices and also all split films. Films are frequently split along the line of the sprocket holes. The film should be run through the fingers in this manner twice: once to catch such irregularities as make themselves manifest along the outer edge and again to catch the defects that exist only in the middle of the film. Every splice should be carefully inspected to note how the sprocket holes match and whether the splice will throw the picture out of frame. All splices that are not properly made should be re-made as directed in Chapter VI.
If there is sufficient time, it would be well to run the film through the machine in the regular way. Thus the operator can familiarize himself with the picture and note every place where improvements can be made by adjusting the speed, for very often a picture may be improved by slowing down or increasing the speed in certain scenes. The flicker varies with the illumination; the brighter the light the greater will be the tendency to flicker, if the machine is not run at proper speed. The operator should know before hand just when his brightest scenes will come on so as to adjust the speed or, in case he must run slowly, so as to reduce the flicker by reducing the illumination. Running the film through will also show every place where the picture goes out of frame and all such places can be corrected. All bad places should be cut out of the film, but not more than necessary. Every additional section cut out of a film will increase the jerkiness of the motion. A few are not noticed, but one often sees in old reels, scenes that are simply ridiculous because too much film has been cut out. Such effects are especially noticeable if a picture is run slowly.
The operator must always be prepared to run pictures at abnormal speeds. It is bad practice to do so but often unavoidable; for instance, if the next number on the program is delayed, it is desirable to extend the picture until it is ready in order that the audience may not be dissatisfied; or if all the seats are filled and people are waiting outside, the manager may demand extra speed so as to make room for the outsiders.
The operator who is wise and has had experience will provide himself with a receptacle in which he can store the pieces he cuts out of films. Saving such pieces and taking them to the exchange will often make an impression upon the exchange management and induce greater care in the inspection of films at the exchange. Such pieces will sometimes be good evidence in the hands of an operator, too, in case he is charged with having damaged a film. While the film is being run through the machine, it can also be measured. Every turn of the crank means one foot of film.
Before the film is wound upon the reel from which it is to be exhibited, an opaque piece of film about two feet in length should be attached to the tail end of the film. This piece of film will in some cases serve a double purpose. With some machines the film can be rewound from the lower magazine into the upper without taking it out of either, if this tail piece is long enough to remain fast to the upper reel after the whole film is run off the upper reel. Thus the operator when through running the picture may immediately change his crank and, without delay, begin to rewind. The main purpose of this tail piece, however, is to shut off the light immediately after the last section of the picture has been exhibited. If the light is left on the screen while the operator slows down the machine, it will cause a disagreeable flicker to appear before the eyes of the audience immediately after the picture is over, and thus leave an unpleasant impression.
The beginning of the film should be provided with a leader from three to five feet long. The purpose of this leader is to allow the operator time to frame his picture and get his lamp adjusted before the title appears, or is finished, so that when the picture actually begins, everything will be running smoothly.
The film must be rewound upon the reel in such a manner that when threaded, the emulsion side will face the lamp. If this is not done, the titles will read from right to left instead of from left to right as they should. It will be well for the operator to form the habit of regularly testing his film by the actual projection to see that his titles are right. There are often many other things to think of and cases of absent-mindedness are not uncommon. If the title shows wrong, the reel may be taken out and turned around; this will reverse it, but ordinarily it is best to wind it in one certain way.
Every operator should have a full supply of good reels for use in the machine and should never let these get out of his house. The reels furnished by the exchanges are often very bad and if perchance a real good one is sent out, some wide-awake operator will surely keep it.
Although it is best to rewind a reel as slowly as your time will permit, it is necessary sometimes to do it very rapidly. The reel from which the film is being unwound should be under a steady tension and some form of brake is often provided. The practice of “pulling down,” which is indulged in by so many operators, is highly reprehensible. It causes the emulsion side of the film to slide over the other and any dirt or dust that may be between the two is thus ground into them. The scratches thus caused soon fill up with dirt and cause streaks in the picture which are commonly termed “rain.” The dirt—especially the carbon dust, which is so plentiful in an operating room and which is very sharp and cuts badly into the emulsion or the celluloid—disfigures the picture very much.
A good film box should be located in every operating room and it should be so conveniently located that the operator will use it in preference to anything else. Such a box should be provided with automatic self-closing covers and should be near the floor, as the film is less liable to dry out there than if placed near the ceiling where the heat is greater. Nothing whatever should be placed upon the floor itself and it should be kept absolutely clean. Although it is very bad practice to run film on the floor and it should not be done, there are occasions when it will be done and, if the floor is clear of all obstruction, the hazard of doing so is much reduced. An operator who, having trouble with his take-up and having run the film on the floor, has had it entangled, will appreciate this fact. The spasmodic bursts of applause which an impatient audience is apt to offer while the show is being delayed are not especially comforting to any one in such a position.
Under no circumstances should film ever be left exposed. Occasional small fires at the aperture plate are unavoidable and in such cases the operator will seek to tear off the burning film and throw it on the floor, and it may then ignite the film lying about. Form the habit of keeping your film under cover; and make up your mind that it is absolutely necessary. Keeping films under cover will also tend to save them from drying out and prevent accumulation of dust.
A slide with the words “Just a moment please,” or some equivalent expression, will reassure the audience; one should always be kept in place and when any trouble causes an interruption of the show, the lamp should be pushed over thus exhibiting this sign. The habit of pushing the lamp over in case of interruption is also a very good one. It is the simplest and most natural way of taking the light off the film and satisfying the audience at the same time. This practice should become a habit. It will be a great protection against fire in addition to the other safety devices. All the work of making ready should if possible be done before a considerable part of the audience is in the house. It is best to let none of them see the process of getting the show in readiness.
As has been stated before, an occasional fire at the aperture is unavoidable. Sometimes pieces of film are torn loose, stick where they are subject to the light, and in time catch fire. A fire thus started may easily consume all of the film between the two magazines and will progress slowly toward the lower one, but towards the upper one very rapidly. If the doors of the magazines are tightly closed and fit tight and if the fire traps are in good order, there will be but a small chance of fire getting at the rolls of film that may be in either magazine. Every effort should, however, be made to extinguish it before it reaches the fire traps. Just what can be done depends upon the design of the machine. In order to be prepared for such an emergency, the operator should study his machine and decide what would be best to do. In many cases the film can be torn off before the fire extends to the magazine and thus break the connection. In some machines the film runs in such a narrow groove that the fire is generally extinguished there without any outside help. Some operators have been known to open their magazines and attempt to remove the film after a fire had started, resulting in burning all their film. It is far better to leave the film in the magazine and trust to the fire traps than to attempt to remove it.
No visitors should be allowed in any operating room during the time that the audience is in the house, more especially when the time for opening the show approaches. There should be nothing to distract the operator’s attention from his duties. The arc lamp should be started a few minutes before the show is to begin so that the electrodes may burn to their proper shape and the light be adjusted. Before the show begins, the house should be made dark for a few minutes. This will make the picture appear brighter.
In case the film tears during a run, some operators have the habit of pinning the pieces together with the intention of making the splice after the picture is run. This practice is well enough for an operator who feels sure that he will not forget about the pin, but with one who is forgetful or absent-minded, or who has a lot of other duties which might take his mind off the film, it is a bad practice. The film may be rewound with the pin remaining in position and cause very serious trouble. It is safer to put the film on the take-up without pinning.
In a general way the points alluded to in the following list should be carefully looked after. This is a list which is used by the Electrical Inspection Bureau of the City of Chicago in checking up operators and their equipment.