Details

Parent Category: Multi-Gauge Topics

Category: Looking After

Care and Repair

 

CARE AND REPAIR OF

 

NARROW-GAUGE FILMS

 

I have been collecting films and projectors for over thirty years, starting with 9.5 but moving on to most other gauges as well over time. The care of films is more important now than ever, as films get older and more used. We may be within a few years of the end of film as a medium with electronics taking over. Keeping what we've got is vital. So I thought that, in the hope that there would be new young nerds entering the hobby to keep it going when us old fogies have gone, I would write down what I have picked up over all those years, to give them a head start.

Let's start with what you need. First, a rewinder. You can't check and repair a film using a projector rewind. Most machines run the mechanism at the same time anyway, causing extra wear. You should not use an editor for film checking - the transport mechanisms can be a bit harsh, especially if you already suspect damage. The best rewinders have two speeds, one-to-one as well as a three- or four-to-one ratio. Ideally, provide some means of holding it still. As you go thru, each turn of the handle winds more film, of course, requiring more effort and the rewinder may get mobile, particularly during the cleaning process. It is important not to speed up the rate at which you check film as the size of the core-plus-film on the winder gets bigger, so you have to turn slower, which is easier if the damned rewinder isn't always sliding about the place.

Second, and probably the most important piece of tackle, is a tape splicer. Mortgage your house, sell your Grandmother, but whatever it takes, get a tape splicer for each and every gauge you dabble in. (There is a piece on an economy 9.5 tape splicer here.) Take your cement splicer and lock it away. Its only use is for joining films. It doesn't repair, it joins film up after youve cut damaged bits out, i.e. the very opposite of repair. There is nothing a cement splicer can do that a tape splicer can't, and with tape you can do so much more. Unless you have (and you haven't) one of those wonderful professional frame line splicers that use heat and pressure as well as cement (better cement than you've ever used, too), you might just as well chuck yours away. You see the results of these pro splicers sometimes, eg where 300' 9.5 reels were joined to make a 900' reel. When you compare them with the hideous mess that one so often sees masquerading as a splice, it's enough to make strong men weep. There is more skill than appears to making a good cement splice, and if you don't got it, don't do it.

For most gauges, the CIR type of splicer using plain unperforated tape is best. The special tapes needed by some splicers can be so difficult to get.

Reading from left to right, we have Super 8 and Standard 8. (The latter is branded Ferrania, and is unlike normal CIR ones in having a special little trimming platform near the hinge.) Next are 9.5 and a Super 8 that uses pre-perforated tape. Lovely splicer while the tape lasts. The next pair are conversions to 17.5mm. (Basically this involves re-sizing the film channel and, the most important and difficult bit, having a punch made of the right size. The double blade for trimming the tape is removed. A sharp blade or craft knife along the side of the film does, if anything, a better job.) Next 35mm - the knob left moves one pair of location pins for shrunken film; the right-hand knob drops the pins on the far right, presumably for the same reason. If I do have to cement splice 9.5, I use the splicer in the last pic; the other is 35mm.

For Super 8 sound, however, particularly stereo, you need a specialist machine that won't cover the mag tracks. The one pictured above misses the track on one side, but wraps round and so covers the balance stripe. If you want to keep stereo, you need one that puts a patch between the mag tracks. The tape itself is also critical. As new, CIR splicers used to be supplied with a ghastly roll of opaque sellotape that marked as soon as you looked at it and was suspiciously sticky. Get PEC or equivalent, where you can read even small print on the core thru a full roll of tape. And no, good tape does not dry out. Cement splices can and do, and they can rarely be completely re-glued satisfactorily; the film is stiffened and distorted by the cement and you end up cutting out another two frames. When sound film is your main interest, this is especially irritating. And if your new join is out of line. For the above reason, never, ever use sprocket patches. Death is too good for the man who invented these.

The remaining requirements are large amounts of blank and opaque leader, tissues, your choice of cleaning fluid (of which more later), a sharp razor blade (you can get one-sided ones), vast stretches of free time and infinite supplies of patience.

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Although I have given up on 16mm features, I seem to have a number of silents and shorts in need of repair. I have therefore modified my 16mm splicer to help. First, I removed the blade as I find it is all too easy to cut the film as well, and now just use a craft knife or single-sided razor-like thing. In order to help with sprocket repair, I have added the extra spools of pre-perforated tape. These are on a cantilever so I can still get the film to the splicer. I won't know until I've used it a bit whether it would be better to have the cantilever the other way round. The support is, of course, made of Meccano (TM) - why make if you have the wherewithal to hand? The tape spools are deliberately left very free, so either can be brought into position. My final mod is hard to see, so I have marked the ends in red. Basically, it is a strip of metal about 3mm from the front edge of the film bed. I pull tape out with a very small-bladed screwdriver and lay it across the sprockets on the front edge. The metal strip then provides an edge against which I can cut the tape at a convenient size to give a wrap-round. This sort of repair is useful because it does not encroach on the picture area, and I use it on most gauges.

Leafing idly thru some late 40's ACW's. I came across one comment that made me stop and think. The context was a discussion of the merits of centre versus edge perforations. The comment referred to the way a film gate is "relieved" around the picture area, ie cut back slightly so that, while the edges of the film are gripped to ensure the image is held steadily in the gate, the picture area should not be in contact with any part of the gate except at the aperture, so minimising the risk of scratching. The point was made that, for 9.5 with its central perfs, the film was not directly supported where the claw enters the perf to do its work. In 16 and 8, the sprocket hole is very closely supported by the side runners of the gate. The suggestion was made that this meant the 9.5 sprocket was more prone to damage and, on reflection, I think there could be something in it. If one imagines gripping a piece of film in a vice, with just an eighth or less of an inch protruding, it will seem very stiff to the touch, and strong enough to cut an incautious finger, A few inches of film would just flop around loose. It would seem logical that, albeit on a very much smaller scale, a similar effect could operate in a projector. There is certainly scope for the film to move in and out fractionally as the claw enters and leaves, which may contribute to splitting. I have often seen 9.5 projectors in which wear to the claw has resulted in the underside becoming notched, so that it may actually catch on the bottom of the perf on the out stroke. It would seem possible that the lack of support around the perf could be a contributory factor in any damage. It's interesting as much as anything because I would like to think that there is some reason for the appalling, incessant sprocket damage one sees in so many 9.5 prints, other than the sheer incompetence of projectionists.

Projectors

Care of films starts with the projector and the projectionist. One of the curiosities of the film world is the enormous amount of attention paid to Film with a capital F as an art form, to Directors, stars, etc, etc, etc, whilst almost totally ignoring the skill that brings it all to the screen. How many books on Film are there? Countless thousands. How many on projectors and the projectionist? If you run out of fingers counting them I would be surprised.

Good projection is pretty simple once you know how, though it is amazing how often even the most basic rules seem to be ignored.

-Make sure the projection path is clean, especially the gate. The gate MUST be cleaned after each reel of film. No buts or maybes or exceptions. We tend to think of film emulsion as fairly soft and easily damaged. This is a good attitude to start from, but it does not tell you how hard a "corn" of emulsion deposited on the gate can be or how devastatingly it can scratch your films. NEVER use anything made of metal or anything that might scratch to clean the gate (or, indeed, any part of the machine). I am suspicious even of the common sort of gate brush with a twisted wire core. What's wrong with a small decorators paintbrush? A scar in the smooth surface of the gate is a disaster. Use wood or plastic or cloth; your fingernails can be handy too. In extreme cases, use some metal polish but never anything more abrasive, and clean it off thoroughly afterwards.

-Thread or lace the projector up correctly. Loops not too big (which can flop about and even get caught on the sprockets), or too small (which can cause the film to pull against the claw and get ripped). Film able to move smoothly in the gate. Retaining rollers all correctly positioned. And always, but ALWAYS use the inching knob God has provided to see that the whole film transport mechanism is operating as it should, loops staying the same size etc, before starting the engine.

There are of course those accursed inventions of the devil, so-called auto-threading machines. They are designed for people who don't know what theyre doing. You're not one of them, are you? You can rarely, if ever, trust an auto-thread. What they actually do is mince your leader, then, once that's gone, move on to your film. You can't stop and take the film out in the middle, correcting loss of loop is chancy and its all more stuff to go wrong. Sometimes you cant escape the auto-thread, but if you have to use one, watch it like a hawk. I always thread my Elmo GS 1200 with the side open so I can stop it if the film starts to follow the wrong path before it squashes the leader into a crumpled mess that will never go thru the machine again. The partial auto-threads you get on some 16mm machines are OK, but seem pointless. With slot-loaders you can't always get at the gate to clean it properly. What you want is a plain, straightforward manual thread machine where you are in charge, not a mechanism designed by a demented engineer on LSD who never showed a film in his life.

-If the projector makes an odd noise while running, stop at once and find out why. Don't just carry on damaging more and more film. A frequent fault is loss of loop, top or bottom, probably due to the sort of damaged film you won't have after reading all this. If the film jumps about on the screen, stop and fix the problem. Sometimes both of the above problems can be caused by film that is very new ("green"), slightly off size or too wet with cleaner/preservative. This sort of clattering in the gate can often be reduced by pressing the film just above the gate forwards or backwards with your finger to slightly increase pressure/tension as the film goes thru the gate. This can, however get very boring and uncomfortable after the first ten minutes. Do not be tempted to tweak the gate pressure unless you get this with all films and you really know what you are doing.

-If you spot possible damage during projection, eg a "jump" in the gate suggesting a bad splice, place a sliver of paper between the layers of film as it takes up to mark the approximate location so you can find and fix on rewinding. If this happens a lot, it's because you haven't checked the film properly. Stop, and do it again. Only rarely will it be a fault with the projector. 

-Ensure neither feed from top/front reel nor take-up has too much tension. This can only weaken the film, pull it off the sprockets or whatever.

-Check frequently during projection to see all is well. Have a torch ready to do this. Think how foolish you will feel if you find hundreds of feet of film in tangled coils on the floor because of a bent take-up spool or belt breakage. I once saved myself much time and money when just such a routine check found the belt driving the cooling fan for the power supply to a Xenon lamp had broken and I could stop before it all blew up expensively.

-Don't project films you haven't checked first unless you can afford to throw them away, which would be a bad thing.

The reason for all of the above Grandmother-teaching is the heart-breaking scale of damage I have so often seen. Nearly all of it is avoidable. Film properly cared for can be projected on a machine in good order time after time with little deterioration.

Film Checking

Now for the hard work. You can't expect a projector to show films safely if the film itself is already damaged. Some projectors are more tolerant than others, but the usual result of damaged film passing thru a projector is that the amount of damage is increased. So, set up your rewinder in a comfortable position, as you're going to be here for some time. Make sure the two ends are actually aligned and that you have a good take-up spool, not a bent one that will snag the edges of the film.

The really detailed checking is most needed with 9.5 and particularly 17.5 and 28, but the general points are universal. To check a film properly, you wind it at a speed that lets you, if you concentrate, see each individual sprocket. You don't need to do this all the time (it makes your eyes go funny), because your principal checking tool is your fingers. Thumb and fore-finger (or middle finger) go either side of the film, on the perforations. Some other bit goes on the edge of the film. Don't grip too tight, to avoid making any damage worse. Now train your fingers to detect the minor variations in feel that say something is wrong. This might be a "snick" at the edge suggesting a split, or a change in the rhythm of the feel as the sprockets pass thru your fingers, or the solid thump of a horrid mediaeval cement splice. Often, it will be a false alarm such as a slight crease in the edge of the film, a blob of emulsion built up where the film has been scratched by some other idiot or, very occasionally, a cement splice that doesn't actually need some attention. 

Faults I have known:- 

-sprockets holes enlarged by the claw. I have seen whole reels of 17.5 with each and every hole enlarged.

-as above, but with the bit of film hanging on in there, not quite detached, or maybe just strained, ready to go later if not treated (a "Chad" I call it).

-straining of sprocket holes, with cracks starting in any direction, or more then one. 9.5 seems particularly prone to splitting from both sides of the sprocket, ultimately even splitting right across the film. With 16, 17.5 and 28 (and 35), a split doesn't have to go far to reach the edge next to the sprocket hole. The risk with this, and the less frequent splits found on the opposite side, is that it will catch somewhere on projection and rip the film badly. You sometimes see old-fashioned attempts to deal with this by cutting on the slant from the outer corners of the sprocket hole, but it leaves a big hole in the side of the film and a source of future weakness. And it may still catch anyway.

-creased film, eg caused by treading on a loop of film. Where this extends across a sprocket, it can initiate a split.

-out and out tears, where the film has been ripped or torn across.

-sprocket tooth punching. Seen most on 17.5, this is a line of dents running the length of the film, caused I assume by the film not being correctly on the sprocket. Ugly on screen and, where it meets a sprocket hole, can easily lead to splitting and sprocket hole enlargement.

-claw scratching. Seen more on 9.5, deep scratching/indentation down the length of the film caused, one can only assume, by loss of loop so the film is displaced in the gate and scraped by the claw.

-bad cement splices. They may be warped/bowed (often at the start of a film), so dry they come apart when you look at them, partly dry so they will wait to come apart until you show the film, out of line so there is a protrusion on both sides waiting to catch on something, out of register (the sprocket hole is in the wrong place or too small because the film has been cut too long or too short or joined badly) or just generally awful with pints of cement sloshed over the surrounding frames making them illegible.

-sellotape. Never ever use it. It can spread itself across several layers of film on the spool and is difficult to remove. But do so.

All the foregoing should make it clear that care is needed in the checking process to avoid making things worse. It is also why you should never clean a film before checking you can so easily snag it or displace bits that might otherwise have hung on. 

The speed and degree of checking obviously depend on what you are dealing with. Many films will be in self-evidently good condition and can be run through fairly quickly, relying on fingers to detect any anomalies. Others can take hours - I have spent 3 hours checking and repairing 1000' (2 reels) of 17.5, and that was in moderately good condition. That was pretty much a frame-by-frame inspection.

Film Repair 

There is no doubt that the tape splicer has revolutionised the possibilities of film repair for the amateur. I tend to work from the assumption that a film should be rescued if it is reasonably possible, and with the minimum possible loss of frames of film. The overriding consideration is that the film must be projectable, without further damage, even if the appearance on the screen or results from the soundtrack are below par. There is no point in spending time on any but the most exceptional narrow gauge films if they are unusable and likely to remain so.

Let's start with the splice, since it is quite possible to make a tape splice that will simply fold in the middle and be unlikely to go thru without trouble. This is an inherent problem of the butt splice, but diagonal splicing is unnecessarily ugly. The solution I have adopted is to make a very slight overlap at the join - fractions of a millimetre. This can be achieved in two basic ways. The "professional" version of the 16mm CIR splicer has one variant which has an adjustable pin on one side of the join. The Super 8 one has under-size pins on one side, which also allows a degree of adjustment. The other way is to put a slight tension on the film when cutting, so as to leave it very slightly longer. Applied to both cut ends this can give just enough extra to give the overlap. The result still has most of the advantages of the tape splice and the extra thickness does not seem to make any difference on projection. As all film shrinks to some extent, the amount of overlap you get varies and you just have to experiment. I only use two sizes of tape for narrow gauge film - about 9mm wide for 8 and 9.5 and about 15mm for 16 and 17.5. 28mm is one gauge I don't got; (I do now, and the next bit is wrong) you'd probably want to use one of the larger tapes designed for 35mm for this.

Another reason why you should repair before cleaning is that proprietary cleaners/preservers leave a lubricant that may interfere with the tape sticking. If you have to tape a cleaned film, wipe the area clean.

The second point before we really start is leader. It is readily available. Do not skimp; use lots at the start and a fair bit at the end. A good long head leader gives you chance to check all is well and to let the machine settle down before the actual film starts to go thru. My Heurtier Universal has a pressure roller that you lower onto the sound drum after starting the machine and it takes a second or two for the film to settle down to a steady speed that will not distort the sound. You can replace leader but not the film. It therefore makes sense to replace the leader when you need to. You often get told not to splice leader; this is a counsel of perfection and most relevant where you are relying on the countdown numbers being actually an exact second apart. In most cases of amateur use, if you can make a good, sound repair, that will be fine and it can be better than cutting a frame or two from the start of the film. At the end of the film, any curling or creasing at the very end can cause the film to catch as it goes thru and so result in damage a foot or two before the end - far better that this should happen to a longish end leader than to the end of the film itself. Leader also protects the film from dirt and dust - it's always the start and end of film that is dirtiest and most dried out.

Particularly for 8, do make a point of keeping the original leaders (and reels) if you join up on to bigger spools. It's so easy to put them back when you sell if you have a tape splicer, and you don't want to keep on buying those big reels, do you?

It's the repair potential of tape that really makes the difference. A range of damage can be treated by simply proceeding as tho' making a splice, but without cutting the film. This can reinforce weakened sprockets, re-join torn film, strengthen splits etc. You may be able to get away with putting tape only on one side. I don't really like to do this as a split, for example, could peel away from the other side and cause a problem. If you are covering an actual hole in the film, then you don't want to leave tape exposed that can attract dirt or even catch on the gate.

Not all repairs call for this treatment. On 9.5, for example, I frequently find pairs of sprockets in patches or in isolation have been strained or split to a greater or lesser degree. These can be repaired two at a time as the tape will extend from the bottom of one hole to cover the next (the second is the one that gets the tape punched out. 9.5 tape splicers only punch one hole, so don't cover two). This means moving the tape to one side of the splicer bed and can make the built in tape cutting blade balk as it is not designed for this. Your razor blade comes into its own here just give the cut a start and the splicer can then take over. (Or you could just forget the built-in blade and use a blade for all cutting, as I do for everything bar 35mm)  In this way, the life of a stretch of film that would otherwise fall apart quite soon can be extended indefinitely. This can prevent an entire film being a basket case because a key section (all too often the end) is damaged and save it from the skip.

In extreme cases, I have had success in using tape to cover one or two sprocket holes where a chunk has been picked out by the claw. You can still see the hole on projection (tho you could reduce the appearance with blooping ink perhaps) but at least it goes thru. This can be preferable to losing frames from a sound track. I have been reluctant to try it for any more than one or two in a row, tho.

Sometimes the claw will rip a sprocket in such a way that the piece of film stays in place by a thread. If this "Chad" can be retained, I think it makes a much stronger repair. I have seen the displaced fragment bent right back to lie flat against the film. With care, this can sometimes be bent back into place. I find you have to proceed very slowly to have a chance of not breaking it off where it is bent - try to re-position it quickly and it just snaps.

On 16 and 17.5 (and 28), I often repair sprockets and side splits with a short piece of tape wrapped round the edge. This way, it extends very little into the picture area. You need to exercise your ingenuity to find a way to do this without having to handle the sticky side of the tape too much, tho' I have found PEC tape quite tolerant of this, marks fading or disappearing if the tape is well rubbed down on the film. I can usually find a way to do this on the splicer somehow. You want spoon-feeding?

One word of warning with all these tape repairs. You have to punch the sprocket holes after each repair, not wait until you've done a whole series. Otherwise , the film won't fit over the pins on the splicer, cos you've taped over the holes. You may end up punching extra holes, not normally regarded as a good thing.

Cement splices, too, can sometimes be fixed. If a join is partly dry, it often won't come apart completely without tearing the film, so a repair is indicated. A little cement judiciously introduced at the right point will usually spread by osmosis into the dry areas of the join. Quickly wipe off the excess (do not be afraid to use fingers for this), apply pressure and, Hey Presto!

If a cement join is so dry it comes apart easily, it can be converted to a tape join without loss of frames. Simply trim to length in the splicer but, before joining, apply a touch of blooping ink to the narrow strip of scraped emulsion left over from the cement join. When dry, splice as usual and it will barely be visible on screen.

Sometimes you will find that trimming the film does not leave a perfect end eg on 16 the outside edge of the sprocket hole may be missing. This usually only affects one side of the join. Probably better in this case to sacrifice one frame, still a gain on making a new cement splice. Alternatively, add a small patch of tape wrapped round the edge of the film. A lazy but sometimes necessary way to fix a cement splice is simply to go over it with tape. Again, the extra thickness doesn't seem to matter too much.

Another possibility, where the sprocket hole is too small or a little out of register, is to re-punch on the tape splicer. You can get a slightly enlarged hole, but projectors seem fairly tolerant - they have to be, some of the rubbish that gets put thru them. You can also strengthen the adjoining sprocket holes to avoid them getting damaged - I often see the holes on one side or another of a cement splice weakened because of defects in the splice.

9.5 notched films present a few problems of their own. Pathescope foolishly supplied lamps for some notched projectors that were too powerful. People were told only to use the lower power lamps for notched films, but of course they never listened. The result was lots of films with cooked titles, shrunken and buckled - I call them Kentucky Fried titles. Sometimes youre lucky to have even a single frame of title left. This is an area in which tape splicing comes into its own in salvaging the otherwise irredeemable. It's also handy to have a notcher, so you can make your own notches when the proper ones are gone, or if you have to do a tape repair over a notch. Just remember, its notch, one frame then the next frame is the still. Cleaning needs great care as its so easy to catch the notches and even easier to catch the slight nicks Pathescope cut into the opposite side from the notch on some films. (there is an explanation for this phenomenon - notches were made before the film was cut into its three 9.5 strips; and misalignment of the punch could lead to encroachment into the edge of the adjoining strip - on two of the three copies.

I tend to err on the side of trying to save films, even if it involves a lot of hard and fiddly work. I just hate seeing any film thrown away. But one has to be realistic sometimes it's just not worth it. What is worth it does however depend on the film/gauge. 17.5 was only produced for the rental market, so few copies were ever made, (in bands of two from 35mm stock). With the regrettable process of attrition that affects film, what you hold in your hand may be the only copy on 17.5 left in the world. It may well need more care than other gauges - I seem to recall it used a di-acetate base, rather than the tri-acetate used for other films. Certainly, it seems to be more brittle and subject to shrinkage. It also seems subject to oily patches on the surface, which can leave a sort of tide line that is difficult to remove. On 9.5, some of the British Lion films no longer exist on any other gauge. Pathescope also produced a handful of copies of Disney films with a soundtrack. One of these would be worth a bit of time and effort. Some films have survived on 28mm that would otherwise have been lost (Perils of Pauline).

Film Cleaning and Preservation

We are talking here strictly for the amateur and for narrow gauge films. Major conservation and long term storage of 35mm film is something quite different.

The objective here is to conserve films so as to maximize their life and minimise damage. So we want to avoid mechanical damage, avoid scratching, prevent drying out, colour fade and sound loss and present the best possible image on the screen.

First, keep your films in a proper container. The minimum requirement is a proper box that will not allow the film to fall out or the end to trail out to get damaged. Better is a close fitting metal box that will help to prevent drying out or accidental damage. In all cases, label the bloody thing clearly and in a position that enables it to be easily read when it is stacked away. Delete old markings that could confuse. You can have pretty and neat and uniform etc if you want, but you must have CLEAR! You can use those clips to hold the end of the film on the reel tidily, but if you are storing with only a modicum of care, you don't really need them. There is a school of thought that says metal cans are bad and only proper, plastic, ventilated archival cans should be used. But this is a counsel of perfection; conditions of storage are about what you can common-sensibly do in the average home. Avoid dust (proper boxes). Avoid damp - better to keep inside even a centrally heated house than a damp shed. Do not transfer from cold to hot temperatures - condensation may form, leading to damage. I suppose it will all get more difficult as films get older, but I've had no problems just keeping them in the house.

Cleaning films is mainly needful for the dirty gauges, ie 9.5 and the really filthy 17.5. I suspect 17.5 projectionists were actually told to put oil on films - I can't see how they got that much on accidentally. Cleaning is also good for eg mag stripe films, as they do tend to shed some mag particles over time and maybe muddy the sound. There is also the preservation issue - you may even delay colour fade.

There has been a range of products over time. Carbon Tetrachloride (now banned as too poisonous - now you tell me!), Perklone and other such stuff are simply solvents you can use as cleaners.  Then there are various proprietary products-: 2.22, Renofilm, Cresclean, Thermofilm, Permafilm, Permanew and maybe others. These all claim to a greater or lesser extent that they preserve, lubricate, improve sound or reduce scratches or all of the above. Trouble is, nearly all of them are able to dissolve the adhesive in tape, so care is needed. I mostly use Perklone for cleaning, and whatever I can lay my hands on otherwise. 

SAFETY NOTICE

All the above products must be used with good ventilation, not for long periods and not drunk.

(Sorry, you have to do this sort of thing nowadays.)

They are of two main types of film cleaner/lubricant/treatment. Some are what I would call the persistent type, that is, you get a wetting of the film and a residual film of stuff on the film. If you use a lot the film can get quite wet. I have tended, not terribly logically, to prefer these as at least you can see you've done something. I also find them better at removing eg sellotape residues. Excess applications may however be visible on screen, and they won't be everyone's cup of tea. The others (can't speak for Permanew - never used it) seem to be more volatile and evaporate off the film more rapidly, hopefully leaving good stuff behind. Actually, Ive used nearly all of them fairly indiscriminately. I've never done controlled double-blind tests on a sample of films over thirty years, but I just feel these things do help to keep film in better condition. Mind you, I also believe that the elephant powder I put by the back door is what has kept my house free of elephants. What they will all do successfully without doubt is help to remove dirt from your films. This is a good thing - it can show up on the screen and build up in the gate and cause scratching.

My cleaning method is simple. I take an ordinary cheap tissue (the more expensive ones may be more linty) and fold it in half four times. This gives a square about 1.5 inches on a side. This is enough clean surface for two passes with 8 and 9.5, one with 16 and 17.5. Wet it with your chosen fluid, fold it round the film and wind. When it gets dry or dirty, stop, refold as necessary to expose a clean surface and repeat. By folding and refolding, I reckon to get at least 8 clean surfaces per tissue. Yes, I am mean enough to save tissues but I also save time and expensive cleaning stuff.

Care is needed to get the correct pressure. If you find damage you missed at the repair stage, you may find the tissue snags and this could do damage. How soon you need to stop and recharge depends - rarely on 8, but on 17.5 I may get a maximum of four turns of the rewind at the start and as little as one at the end before there is so much filth I have to stop. I have repeated this as many as four times without getting all the dirt off.

It may seem somewhat surprising, but this doesn't seem to scratch the film. I suppose it might if you just use the same surface or the same piece of dirty cloth all the time. One thing it does do is to wind the film up very tight. I make a point of finishing with a normal rewind before putting the film away.

With narrow gauge film, we don't get the problems of deterioration that afflicts 35 nitrate, but we can get vinegar syndrome. I recently acquired my first ever 9.5 films with this problem and believe me you can't miss it. The current received wisdom is that some form of absorption thingy may help. I got some from Classic Home Cinema, put them in with the films and sealed them up tight in cans. Can't tell you the result haven't opened the cans. (When I did, it didn't seem to have had a great deal of effect).

Well, that's about it. I hope there are some things in here that will help a few novices along the way.

 

Details

Parent Category: Multi-Gauge Topics

Category: Looking After

Camphor, Vitafilm etc

 

CAMPHOR etc

(These notes are from an American friend.)

As for the camphor - here are my notes:

1 - Best results will be seen on nitrate and diacetate films. Since many of the early 9.5 films are diacetate this is where the bulk of my use comes in, that and old Kodascope silent films prints....As I am unaware of the base for the majority of 17.5, I am hoping they will be early diacetate safety, and therefore also receptive to the treatment.

2 - Worst results will be on reversal film / and some triacetate and the reason for this is that in the nitrate/diacetate films the film will ONLY take in what it needs to replasticize itself, so in essence you could always store these films with some camphor and never experience a problem.....The other films mentioned here will continue to take in the camphor and can over-plasticize themselves...In the case of reversal film it will separate the emulsion from the base...I have actually used this here at work for this very purpose as sometimes I can get a better scan of a frame when it has been removed from its base.....

3 - Since the camphor is in essence "replasticizing" the film do not have any plastic reels or cores inside the can with the film and the camphor, or it will melt. The same effect that can make a brittle film more supple and relaxed, can make a plastic reel or core more gooey......

4 - When the camphor gets used it disappears so therefore within reason, as long as there is camphor in the can then it can still be used..

5 - NEVER, and I repeat NEVER put a recently cleaned film (especially one with something like Vitafilm, or one of the slow drying cleaners) in a can with the camphor or the camphor will react with the chemicals in the cleaner and you will have a liquid in the can that I am not sure what it is capable or incapable of doing (Would need to be a chemist I suppose).

6 - With a pure diacetate film you should see a difference with the general feel and texture after a couple of weeks of treatment... So if you plan to seal things up for a 2 week period you should be fine......Also make sure to seal the can tightly with tape, etc so as to not let any of the developing gases to escape...If they do you won't get the desired results...

I tend to use 35mm cans for the treatment as they allow enough room for a layer of crystals on the bottom of the can, and then I set the film on a metal reel inside the can and seal it up. I usually crush up the crystals inside the bag prior to opening (sort of like mashing up a bag of crisps before opening). I keep the remainder of the unused camphor inside its metallic bag, sealed with a small spring clip.

-------------------------------------------------------------

Vitafilm

I bought some of this stuff. The claims it makes are amazing. However, don't get too excited. By the time it reached me, 380ml cost 50 Euros.

I go it from www.wittner-cinetec.com, a site well worth looking at in its own right. Wittner seem good, which tempers somewhat my natural

scepticism about the claims for Vitafilm.

I followed the instructions and immersed 2 900' reels of 9.5 in Vitafilm for 24 hours, then drained the surplus off and placed the film in a sealed can. I opened the can last week. The film in question was a rarity in being one of the very few 9.5 films I have come across that have Vinegar Syndrome (VS); there was a very powerful pong from this film. Vitafilm claims to be able to cure it by the method I have outlined. If you are familiar with VS you will know that one effect is making the film go all floopy. There seems to be a loss of symmetry in the film, with one side or other being slightly longer so that the film twists and looks decidedly not flat. A practical effect is that the film has to be wound and re-wound under considerable tension or the film layers wind very loosely and sag towards the bottom of the reel, so that it becomes impossible to get it all on its reel. I doubt Vitafilm can cure this, tho' it could stop any further deterioration. 

I can only give a progress report at this stage. I had a nasty shock when I opened the can; the Vitafilm had attacked my beautiful, pristine black Pathspools. Large areas were covered with little dots or bubbles. It was not quite as bad as it looked, as a lot of the bubbles just wiped away, but the paint was left feeling slightly damp; I had to bake the spools in the oven (sans film!) for 10 minutes to dry this up. However, my reels will never be quite the same again. Seeing as I would not care to risk a fibre reel in anything remotely like Vitafilm, this means the only option is an unpainted, all-metal reel, as I would not feel comfortable using the enamelled 1000' spools either. 

Obviously, the floopiness of the film has not changed, but the vinegar smell is at the very least greatly reduced; in its place is a fairly strong smell of Vitafilm, and I cannot quite persuade myself that I can't detect a faint whiff of vinegar underneath. The film still appears pretty wet, so I may have to dry it off a bit and leave it a while before I can really tell. Will keep you posted.

 

Details

Parent Category: Multi-Gauge Topics

Category: Looking After

Amplifiers

 Looking After  

Circuit Diagrams

 

OLD PROJECTOR AMPLIFIERS

 

Before we start, note that safety must be paramount. Old amps use high voltages and can kill. Do not put yourself at risk.

I accept no responsibility for you damaging yourself.

 

I have only ever had a very limited knowledge of electronics; I can just about do electrics, ie wiring motors, switches and lamps, but replacing the odd valve or capacitor, or fitting a solar cell, is about as far as I have gotten and I am forced to rely on others. So I thought that a basic guide to what do with old projector amplifiers could help you to avoid unnecessary damage to old amps. By forcing me to codify what I already know, at least in part, and to learn more stuff as I get additional guidance from those who do understand this stuff, it should help me too. Please excuse me if I get too simple for you I want to be as basic and simple as possible for beginners and for me. I am seeking only to help people avoid damage and overcome a few of the more common problems. For me, anyway, getting beyond that requires the services of someone who actually knows what they are doing electronically. And if you do, you dont need this.

My thanks to Paul Schimmel who has been my technical consultant for this.

 

READ THIS FIRST!

 

The very first point is that you should NEVER CONNECT OR SWITCH ON AN OLD AMP without first taking precautions, both for safety and because some electronic components deteriorate with time, and powering up the amp with damaged parts could do extensive damage, causing far more trouble than following a few simple procedures first. The longer the machine has been out of operation the greater the risk. Always visibly inspect the internal wiring - old rubber insulation can just perish away leading to a real risk of electrocution and/or fire. Whilst inside, also inspect the condition of the large capacitors, any with bulges or leaks will probably require replacement. Note that many machines do not have a separate amplifier switch if you plug it in, the amp is on. (The 9.5 Vox incorporated a power connection into the speaker plug to pre-empt this problem, a useful safety trick - Pathé obviously knew about 9.5ers).

This is not good, for the reason given above, but also because, with valve amps in particular, if you switch them on without a speaker plugged in, this, too, can cause serious damage. (It is possible, however, to replace the speaker with a dummy load of appropriate value; normally 16 ohms is a good starting point). Another important factor is that no amplifier likes being connected to a speaker of a lower impedance rating than it is designed for (higher seems to matter less). This means you should not try to use a 4 ohm speaker with an amp designed for 8 or 16 amps. It is also important to note that if you wire two 8 ohm speakers together in parallel, the impedance drops to 4 ohms. Wired in series the total impedance is 16 ohms. So many machines have been separated from their original speakers that this issue becomes crucial. A lot of speakers are marked but, if not, the ohm range on even a basic multimeter will help. The multimeter only tests using DC and the displayed results will read approximately of the loudspeakers impedance (which is normally measured using a 1kHz sine wave). Eg around 6 ohm on meter is probably an 8 ohm unit, around 12 is probably 16 etc. Some amps - the Heurtiers, for example - can be adjusted, in the same way as for mains input voltage, to feed speakers of different impedances.

Yet another issue with older amps is that the speakers are often mains energised. This means that, instead of the permanent magnet modern speakers use, the speaker coil is an electromagnet, powered by the mains or even by a supply of up to 400v from the projector. Unless you are a complete expert or a Museum, this is one area where changing the original is wholly justified you really do not want 240 -  400v in your speaker cables. (Nor, of course, do you want to try connecting a powered speaker cable to a magnet-driven speaker). This means considering not only a new speaker, but also internal changes to the amplifier to match the output to the new speaker. More on this later.

PRECAUTIONS

OK, so what are these preliminary precautions of which I speak? The first step has got to be finding out as much as you can. There are various resources you can call on Cinerdistan is just one; some others are in the links section in Miscellany. Elsewhere, eg Oldtimer Cameras, you may have to pay for projector instructions or manuals, but it could be well worth it. However, for many machines you may be unable to get all the info you need and you just have to check out the machine as best you can. What are the projector and lamp voltages? Many older machines need 110v, but this may not be so obvious if they have lost their original transformer or, perish the thought, resistance. (The GB L516, and presumably its siblings like the K516, used a resistance connected to the side to reduce 240v to 110v for the lamp, but used mains power otherwise). Is there a speaker? Is it marked? Does it have a permanent magnet?

I have 2 GB L516 machines that have been adapted. Either can be connected to a box (left) which contains the necessary circuitry and transformers for the lamp and the speaker. One lead plugs 

into what was originally the resistance socket on the side of the machine, to connect the lamp and its transformer. To avoid trying to shoe-horn additional stuff into the main body of the machine, the original speaker lead is used as far as the box, where various gubbins sort things out, so that a normal speaker can just be plugged into the box. This limits the high voltages to a short stretch between projector and box. 

Then obvious stuff like are all the valves there? Is there any visible damage to wiring, eg rotted insulation. I dont much like relying on old wire even if it looks good, you don't know what's going on inside. The next step is equipment. Obviously a basic multimeter, so you can test circuit continuity. Soldering iron and the usual tools. And dont forget to record what goes where when it comesto any dismantling I often draw a sketch of wiring/connections. Even what valve goes where is something I find challenging.

VARIAC

 

In avoiding damage to old valve amplifiers, a Variac is highly desirable. If you dont know, its a specialised form of transformer that can output anything from 0v to full mains. The big ones are able to take the 10 amps or so that many lamps use, but these are expensive, unless you get lucky with a second-hand one. However, amplifiers dont consume much and a 1 amp Variac should be ample as long as you dont turn the motor and lamp on. The principal value of a Variac is in feeding the amp with a voltage low enough not to cause damage if there are problems, but it also helps to gently re-form the electrolytic capacitors; these can often be revived by an initial low voltage, where an immediate application of full voltage would not do this, leaving them non-functional and leading to serious damage.

I was lucky enough to acquire a low-power Variac from a friend, tho it was naked. A few years ago, I attended some metal-working classes at a local college. They had big metal slicing and bending machines, so I took the opportunity to cut and bend two U-shaped sheets, so that when put together they would cover all six sides of a cubic box. This was just on spec with no particular use in mind, but they provided a housing into which I could just about squeeze my Variac. The other thing you need with a Variac is a standard 100w house lamp (I suppose youll have to make do with 60w nowadays as 100s are no longer available, or 2 60s in parallel). This is wired in series with the output from the Variac (before it reaches the projector) and serves two purposes. First, it limits the maximum possible flow of current (and therefore the damage that might be caused) and second, if it starts to glow more than just a bit, you know something is going wrong. The mains input is the wire coming in from the right, the controlled output goes thru the lamp, via a standard connector so I can just take the lamp out of the circuit when I want.

Using a safe level of feed from the Variac, the valves will receive enough power to operate the heaters, so you will be able to see the glow. If you cant, something is wrong. Paul Schimmel guided me through testing a Danson in this way. One valve persistently failed to heat up; in the end it turned out that only one of the three machines we had available on the bench had a functioning version of this valve and applying full power would undoubtedly have done far greater damage. S-l-o-w-l-y bring up the voltage to the amplifier, using the Variac, whilst listening to the speaker and looking for a glow from all the valves. Stop immediately if there are any signs of trouble such as obvious burning smells, smoke etc. Hopefully as the voltage gets above 80% youll be rewarded with a bit of hiss and hum from the louspeaker. Keep advancing the voltage, once at 100% leave it to settle and maybe try putting a piece of paper in between the exciter and PEC. Hopefully youll be rewarded by a plop noise from the loudspeaker. If all seems well disconnect Variac and try a film. If sound is excessively humming, the main electrolytics may require replacement; if sound is distorted the paper coupling capacitors may be leaky. See below for more tips. Do not run an obviously faulty amplifier for any length of time in the hope it will get better: you run the risk of damaging the valves, the transformers and yourself.

AC/DC Amplifiers

 

Although Britains mains supplies went mainly AC from the 30s on, for reasons of versatility and/or cheapness and/or lightness some machines have what is known as an AC/DC amplifier. In this type of design the mains transformer is dispensed with and the amplifier connects DIRECTLY to the mains. This can be highly dangerous and live amplifiers should only be worked on if powered up via an Isolation transformer. Early machines often have unpolarized mains connectors and if you are unlucky the amp chassis will be live! Note it is normal to mount the amplifier chassis to the main chassis via insulators and fit plastic knobs so that the ordinary user is not exposed to danger. Projectors having AC/DC amplifiers include the GB L516, Ampro Educational and (in a very sophisticated form), the B&H 631 series.

Remember that a Variac is not a transformer in the conventional sense and offers no isolation from the mains.

 

VALVES

 

We need to consider the types of valve you may encounter and what they do. Valves basically do four things in a cine projector amp:-

Rectification of the incoming AC current to provide the DC the amp needs;

Pre-amplification of the various inputs to the amp (photocell, Microphone etc) followed by further amplification until the signal is large enough to drive, inevitably:-

Power amplification, the output stage of the amp. Here the signal is given its final boost up to sufficient watts to drive the loudspeaker via the output transformer. Simple amplifiers may have just one power valve, more advanced designs will have two power valves working together in what is known as push-pull. Generally speaking any amplifier delivering more than about 3 watts will be push-pull.

In addition to the above some amplifiers also use a power valve to supply the Exciter lamp for reduced hum on optical sound.

Here is a list of the sort of valves you are likely to find in each of these categories:-

Rectifiers: 5Y3, EZ40, EZ81 etc

Pre-amplifier valves: 6SN7, EF37, EF86, ECC83 etc

Power output valves: 6V6, EL40, EL84 etc

There are also dual types such as the ECL82 which combine a pre-amp and power amp in one glass envelope. 

Obviously, the earliest valves you are likely to find in a projector will date from the early 30s, unless you find a very early sound-on-disc machine. The earlier valves tend to be large, glass-envelope jobbies, or smaller, metal-envelope ones, with a large central pin, with a locating stripe down the pin, and four to six moderate-size pins of about 3mm diameter or so. Later valves are smaller and have thin, almost wire-sized pins, with a gap in the circle of pins that deals with location. There are all sorts of minor variations; some have a top connection as well, some are fitted with metal shrouds. One type has pips moulded into the side of the glass envelope to assist correct location. Some pix and more info are at the end. 

Capacitors

 

These are the most frequent cause of problems with old amps valves fail far less often. The problem is that, as they age, capacitors become less and less able to deliver their intended performance. This can result in loss of volume in the output or more serious problems such as allowing the wrong voltage to pass to a valve and overload it. A vintage amplifier will normally contain large Electrolytic capacitors used in the power supply circuitry and smaller paper capacitors used for coupling signals between the various stages. Electrolytics can suffer from drying out and lack of use can cause their capacitance value to fall. Often they can be revived by re-forming. This involves gradually ramping up the voltage applied whilst limiting the current in the circuit, using the Variac in the way described above). A reformed electrolytic should draw less than 1mA, but it may take 24hours or so to reach this value. If the capacitor is visibly leaking or bubbling then it should obviously be replaced, but it is cheap enough and usually relatively simple just to replace them all as a matter of course. The main smoothing capacitor is the one located immediately after the rectifier and the most likely to overheat and fail if the amplifier is not raised gently from its slumbers in storage. 

Sometimes valve amplifiers make use of multi-section devices having 2 or 3 capacitors mounted in one can with colour coded tags to identify the different sections. The colours are normally described on the can itself. The outer capacitor is the section intended to be connected to the rectifier. Paper capacitors, on the other hand, are prone to absorbing moisture from the atmosphere and becoming leaky. In particular a leaky capacitor connected to the grid of an output valve can ruin a perfectly good valve and/or transformer. Suspect paper capacitors should be replaced with modern Polyester or Polypropylene types with voltage ratings equal to, or greater than the part being replaced. To check for leakage, measure the DC voltage on the grid *after* the capacitor. For a typical output valve, this voltage should be below 1v. Any paper capacitor made by Hunts should probably be changed on sight as these are notoriously leaky.

Resistors

With age, resistors can drift high in value. This doesnt seem to be so much of an issue in cine projectors compared to domestic radios. Presumably something to do with the latter being in heavy daily use. Resistors should be visibly checked for signs of overheating, any suspect can be easily checked with a multimeter (with one leg removed from the circuit). More detailed diagnosis will require a circuit diagram. For the absolute purist, there are originality issues here, too. I have heard that old radio buffs will go so far as to hollow out old, duff caps and fit modern ones invisibly inside to maintain appearances. This is a bridge too far for me, tho I admit I would like to retain the old design of an amp and the valves, which are very often available, maybe even the photocell. Bear in mind these will have been specifically designed for a specific projector and can therefore be good. They can also be poor, of course, but there is no guarantee that a non-specific amp will do that much better.

Here is an example of a projector amp, a Danson. Originally Italian made, some parts of it came to be replaced or added in this country. This is one of a batch of no less than four that I had on hand. There are various minor differences, but nothing very major. The oddest feature of the Danson is its switching. There is a switch on the base of the amp, just inside the door. On one machine this is a push-to-make switch that presumably acts as a cut-out when the amp door is opened. Others have a standard toggle switch; this may, of course, be a customer modification rather than an original feature. There are switches on the front panel for sound (this actually operates the exciter) and projector. But the projector switch does nothing until the on-off switch incorporated into the tone control knob is switched on. The valves light up whether this switch is on or not, tho this could be just the heaters.

 

                     

A few shots of the amp out of its shell. Removal is mostly straightforward, four screws from the bottom of the machine to undo and two connectors, a multi-pin job next to the tranny and a co-axial type, which is the feed from the PEC. BUT BE WARNED! It is essential to extend the front feet of the projector (used for tilting) to their maximum extent before moving the amp. You can see from the absurd capacitor standing right up from the rest of the amp how hard they worked to shoehorn the amp into a very confined space; another problem is that the big tranny tends to foul the socket for the front feet and, if not unscrewed, the shaft of the foot would prevent removal of the amp altogether.

Note that on this amp, the speaker socket is a jack that I fitted instead of the unusual 3-pin Danson type, which I don't have for this particular machine. I also had to replace the fuse carrier next to the tranny at the back; it was loose because the threaded plastic body was disintegrating. There was also a problem with this machine at the amp inputs behind those voltage change pins, with a loose connection stopping the machine working at all.

Pix 2 and 3 are before and after pictures showing the change of capacitors. It is easy to see that four tubular ones have been replaced by much smaller, square, red ones. Top left is a pair of caps; the replacement for one of them is, as you would expect, much smaller than the original. But the other is if anything larger, and I have no idea why. The three blue caps bundled together top right deal with smoothing for the early stages of the amplifier and are less critical to change. So if you are able to solder, the job is not too bad, tho later machines with printed circuit boards are a whole other kettle of fish.

When there were only 3 machines (the fourth came a bit later), we found only one functional EZ40 valve between them, tho the rest seem broadly OK. The valve layout is helpfully printed on a plaque. Looking at the LH pic, the front are 2 x EL41 and the aforementioned EZ40. An ECC40 and EF40 complete the line-up. The EZ40 is the rectifier providing DC power to the whole amplifier. The EF40 is a pre-amp pentode which amplifies the output from the PEC. The signal then goes to the volume control. The ECC40 is a double triode valve. The first section amplifies the signal from the volume control further and the second is the phase splitter used to divide the signal into two halves suitable for feeding the 2 EL41 power pentodes. These form a push-pull output stage giving approx 8 watts into the speaker.

Other thoughts

One way of dealing with all this is just to bypass it. I have a 9.5mm Super Vox that hasn't had an amp at all since I got it 40 years ago. Instead it has had a diode/solar cell, which I plug into an external amplifier. PA amps with microphone input are often sensitive enough to accept the output from such a cell without any amplification. I have, however, used a variety of pre-amps and a variety of amps. At one stage, I used a hi-fi amp, but they are really not suitable for this work in my view, nor are hi-fi speakers. I now use specific projector amps and speakers; at one time, I used the mic socket of a B&H 621, tho I think the amp got too hot without the motor fan in operation; currently I am using a B&H amp which is a 110v transistorised unit designed to fit in place of the original valve amp in the 620 etc series. I've built it a little box of its own and of course I always have 110v on tap to power it. You will find a great deal more about this topic, and possible suppliers, in the Lost Chord section under 9.5 sound. But remember, the First  (or is it Second? I can never remember if Never Throw Anything Away comes first or second) Commandment still applies;

Thou Shalt Not Bodge!

 If you can't do any good, at least do no harm .Try to ensure that if you do bypass it, the old amp is not damaged and could be restored by someone with more skill or more regard for originality. And if you remove parts, dont chuck them away. Often, old volume controls etc are very noisy and crackly in use; I am told that a spray with Contact Cleaner such as Servisol can help. It can probably help with other stuff, too, like valve bases, in & out sockets etc. Poor connections are one of the obvious problems of aged amps A standard irritation is the failure of projector manufacturers to use standard connections, whether for inputs or outputs. I keep several short leads on hand with a jack plug one end and a trailing speaker socket at the other. B&H are one of the worst offenders with their Jones plugs and off-standard speaker sockets and plugs. I keep meaning to get around to making up a short lead for them, too. Most recently, I managed to replace the Jones-type mains input receptacle on a 643 with a Euro type, just using a sheet of metal and the original holes to mount the new socket.

 

Valve Pictures 

Valves are one of those infuriating and incomprehensible pieces of technology. There is a huge range of types and sizes the ones shown here are just a small selection of ones you might find in a projector amplifier. Its impossible to understand why they needed so many. Each manufacturer and/or country had their own numbering system, creating a need for vast lists of equivalents. There are thousands lying around, but the ones you have in large numbers are never the ones you need. Valves are always labelled with a special ink or whatever that is specially designed to fail rapidly in use, due to friction of handling and heat. So many of those valves you have are impossible to identify. Yet another area where the non-specialist has to plough thru masses of material to find a few grains of sense. One of the few good things about the Cold War was the backwards technology of the Eastern Bloc; for some years, valves were still available from the East when the West had stopped making them.

Note that some of these have a central locating pin, others use pin layout for location. !930s to 1950s.

 

The two on the left are metal; the other two coated glass. !930s 1940s.

The last of the Age of Valves. You may just see the pip on the glass base of the LH EZ40, reproduced in the metal base cover of the valve on the right.

Various covers are used to hold and stabilise valves, from the simple spring to a type which is very common but which I naturally couldnt find when I took this picture. It's a cross between the two covers shown here , a solid aluminium sleeve, with a spring at the top, and a base that fits over and twist-locks onto the valve base. NB springs and covers can be very tight I once broke the pip off the top of a valve with a spring clip like this.

 

 

While we were doing valves, I thought we might as well do Photo Electric Cells (PECs), which also come in a range of types and sizes; note top left one with the late small-pin valve base. Note that PECs should not be exposed to light for any length of time. If not mounted in a projector, they should be stored in a light- proof box.

 Looking After  

Circuit Diagrams

 

 

 

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