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Posted by Randy Stankey (Member # 64) on 09-01-1999, 04:22 PM:
Lately I've been seeing little white tick marks developing down the right hand edge of the picture on one of our proj.(Century w/turret and Speco LP-270 platters)
When you examine the film, there's a narrow strip of abrasion on the 'inboard' edge of the film, just inside the sprocket holes. It's only about 1/8 inch wide.
I've checked the roller alignment and there's nothing scraping the film. I've also checked the proj. itself for burred rollers or out of line film path. (I check all rollers every month or so PLUS quick checks every morning.)
Only thing I can guess is somethng in the platter's brain, or maybe the trap is somehow scuffing the film.
Our platters have the 'old' kind of brains without the guard rollers around the outside. (Like Potts/Strong brains)
They've been a pain in the butt since day one.
The reason I say maybe the gate is scuffing is because that happened on another proj. It used to have a major 'dandruff' problem. It looked like it was running IB-Tech even when it wasn't! (That was fixed long ago.)
Thanks for any help!
Randy
Posted by Brad Miller (Member # 2) on 09-01-1999, 06:59 PM:
Is there any pattern to the white marks? Do they sit still on screen or roll upward or down in any pattern?Also, which side of the film is this happening to? Base or emulsion?
Posted by Rick Long (Member # 213) on 09-01-1999, 07:43 PM:
We had a similar problem at one of our theatres using Speco LP-270 platters and Cinemeccanica Vic-5's. Platters sit on the left hand side of the projectors as you face the screen.
For about three months following the installation, everything went fine. Then we started getting panic calls regarding scratched prints. "Ticks" is a perfect description. The damaged manifested itself as a series of slightly diagonal white ticks on (I think) the right hand side of the screen.
The problem in troubleshooting this was with the intermittancy of the problem. Everything would run fine for weeks, then suddenly these scratches would appear. Endless hours of running test loops through the platter and projector combination could not reproduce the fault.
It came to a head one Monday morning when I got a call from one of the Corporation's Vice Presidents (steamed about one of their art films being scratched over the weekend).
"This is our last print", he warned, "Don't f**k it up".
Repeated loop trials that morning proved fruitless. Jim, the projectionist, said "I'm not 100% sure, but I think you can see light evidence of scratches on the print before they become really heavy. I've been running this trailer-pac since Friday and mounted the new feature this morning. If the problem is still there you might see it on the trailer-pac.
Where better to look for scratches than on the projected image? As the first show started, I went to the front row, sat down, and leaned forward squinting at the screen for any sign of scratches. Suddenly I got a pat on my shoulder. I turned around. It was a patron - an older fella. "Son," he said, "Don't you think it's time you got glasses?"
To make a long story short, out of fustration, Jim began placing the print of the platter sound-track down (as per Speco's
instructions). That was in 1988. To this day the problem has not re-occured.
For what it's worth....
Posted by Brad Miller (Member # 2) on 09-01-1999, 07:58 PM:
Not a good idea there. Running soundtrack down puts the emulsion on the abrasive side! I think what you had Rick was a fluke and nothing more. I'm not so certain it is on the platter anyway. The only way a SPECO could scratch film would be if there was a misaligned roller or if the film got caught in the brain and dropped down in between the two small rollers that fit together (just after the feed arm). The only other idea I have on that is the secondary roller, just after those two sandwiched rollers. As you've probably no doubt seen, the film will straighten up and almost lock in a straight flat position as the SPECO brain pulses between on and off, commonly forcing a little extra film through the other end of the brain. When it tightens back up, it might be jumping that second roller.
Personally, I always skipped that roller as not threading around it added just a touch more of tension and provided a protection roller, similar to a Strong platter's brain for startups, since the SPECO platters always wrap a full time at the start of each show. (By the way, I'm referring to the older SPECO non-removable brains.)
The only way running a print soundtrack down would make a difference is if the last roller in the chain was precisely mis-aligned just perfect enough so it would just barely scratch on the edge of the film...BUT when you flipped it, it would've been causing severe emulsion scratches to the soundtrack! Look at the odds here. That must've been something else as it wasn't the soundtrack down thing.
Randy, can you send me a sample of this damage? Perhaps a trailer with definite marks on it? I can find the cause from there.
Posted by Rick Long (Member # 213) on 09-01-1999, 11:37 PM:
I would suggest, also, isolating the problem as much as possible - taking into account that there are three possible components that could be causing the problem - projector/soundhead, feed rollers, and platter.
Start by making a loop of virgin film long enough to go through the projector and soundhead. Run it (obviously sound-track toward you, emulsion side toward the lamphouse) under projection conditions (lamp on, dowser and change-over open). Guard as much as possible, the loop being scratched by rubbing against the projector casting,
ect.
It does not take long to run the equivalent of a hundred or so runs. Carefully examing the film for signs of the type of damage you have experienced. If no signs of this damage are present, switch apertures (Flat to Scope or whatever), and try it again. Plates that are not properly back-filed can expand under the heat from the arc, and a sharp edge can dig into the emulsion. (This is why I suggest trying this test with the lamp on).
This will indicate whether the projector is the source of your problems, or not.
Platter and rollers as sources of scratching can best be checked by running the virgin film from the platter and through the projector as above (ie lamp on, ect. in other words, your normal threading pattern) and watching the screen. If you see a scratch, immediately stop the projector (using your hand against the flywheel, if necessary - you want to stop as fast as possible). With the film still in place, try to isolate where the scratch is occuring.
Finally, start keeping a record of who was running the booth on the particular night that the scratch occured. Is it possible that someone is accidentally going the wrong way around a roller, ect?
Good luck.
Posted by Stephen Jones 1 (Member # 114) on 09-02-1999, 04:55 AM:
I know this may sound like I simple question but are your loops too big? I had the exact same problem with alot of the prints at my theatre. I narrowed it down to when they were being scratched and it was always after the same projectionist. I went up one day to check his threading and sure enough his top loop was way too big. We have Christies at our theatre and even with the top loop too big it doesn't necessarily sound like something's wrong. Most improper threading can be heard once you're familiar with the way it's supposed to sound; of course with Christie's the sound is constantly changing. Anyway... I found that the loop flapping back and forth was causing green and yellow tick that traveled down the picture. The film was hitting some part of the projector at a different point on the frame every cycle causing these tick marks. Nothing sharp or anything was poking out any place, but it was the hard flapping of the film that did it. I got together with him and showed him what he was doing. That was 9 months ago and I haven't seen a tick mark since.
Posted by Gordon McLeod (Member # 33) on 09-02-1999, 10:26 AM:
I have also seen this from oversized upper loop hitting the linkage on the apperture changer on a Vic 5/8 that is above the gate
One of the higgenbottoms from specco did say that scratching was probable if run soundtrack up for some reason and they would not be more specific
Posted by Aaron Mehocic (Member # 15) on 09-02-1999, 10:56 AM:
I also have heard that running soundtrack up will cause "ware" on the emulsion (I assume that means scratches). I've been operating projectors for almost eight years and I can tell you that, in my opinion, it does not matter if the soundtrack rests on the platter in the up or down position as to if a scratch will occur. When I trained, we ran soundtrack up. Now, at the request of the manager (and former manager who had a love affair with the SPECO platter), we run soundtrack down. Personally, I see no differences in scratching. In defense of Brad's earlier comments, however, I do not run the equipment he is refering to. Only the SPECO's with removal brains.
Posted by Brad Miller (Member # 2) on 09-02-1999, 03:59 PM:
Sounds like the Higgenbothams are just relaying that out of date information from SMPTE 2 or so decades ago in reference to the soundtrack down thing and haven't actually taken a look at their own product closely enough.Assuming all the platter rollers are freely turning and there is nothing projector related causing a problem, there are only a few places where a SPECO (older model) could possibly cause a scratch.
#1 Everyone knows that the large roller in the brain is darn near impossible to get to spin. Running soundtrack up puts the base side on it with no damage, whereas running down puts the emulsion on it laying light scratches the SDDS and SRD tracks! Granted the tension here is very minor so this is usually not a problem for awhile, but will show up on prints after a few months. Yeah, that's a good idea. Who cares about digital sound anyway?
#2 Everyone knows the SPECOs can't get fully up to speed upon startup and a full wrap around the brain always occurs. Well, if your soundtrack is down on the platter, you've got yourself nice wavy emulsion scratches for up to the first 30 seconds of your first trailer! Hmmm, a nice way to start the show. First impressions, remember?
#3 Look at the two (now 3) stationary rollers at the top of the elevator. Let's say the projectionist misses one of them or during threading the film pops off of one of them. Well, if it falls off away from the platter, the failsafe will not allow the machine to run. However, if it falls in the direction of the shaft, you're running soundtrack down and taking into account the high tension of the takeup...you'll get horrible emulsion scratches running vertically thorughout the print! Wouldn't that make for a fantastic presentation? It's happened and is very easy to do.
#4 Take a look at the last roller in the chain. In the mid to late 80s there was a retrofit for this roller assembly so the operator could pull a knob and release the entire roller shaft to move to another deck. This metal is made out of extremely flexible material and is very easily bent. If it is bent just a little bit too far down, and you're running soundtrack down, then you've got yourself glorious diagonal emulsion scratches! Wow, just sounds too good to be true, eh?
And if that isn't enough, I've personally been studying the effects of winding emulsion in vs. emulsion out for many years. All of my findings clearly result in winding emulsion out on ALL polyester prints. But don't take my word for it, nor the very, very old SMPTE recommendations, conduct experiments for yourself.
Running soundtrack down is a bad, bad idea due to the winding effects of polyester film and most importantly the higher risk of damage from operator misthread or equipment misalignment.
Posted by Rick Long (Member # 213) on 09-02-1999, 06:17 PM:
Brad, being very very old, I remember when the S.M.P.T.E. emulsion-out recomendation came out. I was running 2000' reels at the time (not hand-cranked, mind you), and I immediately adopted the practice (despite the objections of the other even older projectionist who shared the booth). You are right, I began to see a noticeable difference in the projected image.
I understood, at the time, that this was due to the plastic "set" that occurs when the film is spooled onto reels with 4 or 5 inch cores.
Given that the film spends a lot of its time on these types of reels, during shipping, how long would you say it takes for this problem to resolve itself when using the emulsion-out winding on platters?
Posted by Jason Burroughs (Member # 68) on 09-02-1999, 06:20 PM:
While its been a while since I've worked with a SPECO here's what I can recall. As Brad mentioned the platters take a while to get up to full speed. Also some of the rollers in the "brain" do not rotate due to the lack of pressure on them and the film "glides" across them. One thing that I have seen happen as well similar to what Brad had mentioned is on the threading on the takeup side a projectionist didn't skip a roller but instead the film was ridding on the flange of the roller itself, if you can imagine it. The film did not find its way either into or completely out of the roller I caught this about half way through after I took over after the other projectionist during a routine check of things. Evidently there was a little burr on the edge of the roller flange, because on the next run there were will tick marks on the first half of the movie.
Posted by Brad Miller (Member # 2) on 09-02-1999, 08:51 PM:
Rick,I think you've got your winding backwards on your post above. SMPTE recommended the practice of winding emulsion in for reels where the outer edge of the reel was greater than three times the size of the core. This was also intended for triacetate film stocks. With platters, the center "core" is so large that "benefit" is not there regardless of which way you wind the print. However, I have found through years of testing on my own that emulsion out winding, even on 2000' or 6000' reels is far superior in terms of storage (warpage and shrinkage) than winding emulsion in. Even running changeovers, I have never found an exclusive emulsion out to pose the slightest problem.
Posted by Rick Long (Member # 213) on 09-02-1999, 09:56 PM:
Brad, you're right. I had the terms backwards -sorry about that. I still insist that on 2000' reels, it made a difference.
Posted by Brad Miller (Member # 2) on 09-02-1999, 11:05 PM:
What film stock? Projectors used? Lenses used?
Posted by Rick Long (Member # 213) on 09-02-1999, 11:26 PM:
1969 - Paramount Theatre, Peterborough, Ontario, Simplex E-7, Peerless Magnarc lamps, (7 & 8 trim), 96' throw, Ross lenses (British), acitate stock (standard for the era), Using 35X50 binoculors to focus the picture.
Posted by Brad Miller (Member # 2) on 09-02-1999, 11:30 PM:
That's why. Old acetate stock, old lenses. Everything there is very outdated by today's standards. But for the time, SMPTE's recommendation was probably a good one. Just not today. 
Posted by Randy Stankey (Member # 64) on 09-08-1999, 03:44 PM:
Sorry for the lag time in the reply, here. I'm a technological 'have-not'...
I've pretty much eliminated the platter from the list of suspects. I just sat there on a stool and watched the film run for a while and even though I have the old, non-removable brains on my Speco platters, they are pretty much okay.
I'm back to investigating the rollers. I think it's a pad roller, but I'm not 100% sure.
The damage is on the extreme right side of the picture. Only a few inches to the inside of the masking. In fact, the 'keystone' effect cuts it off at the bottom of the screen. It appears as little white dots. At first glance, I thought it was DTS code but then I thought, "HEY! DTS is on the OTHER side of the screen!" At first, there are only 3 or 4 ticks. Then, over time, it builds up until there are about 50 of them. They DO appear to travel up the screen. Looking at the film under the light reveals that there is a thin strip of abrasion down the inboard/non-soundtrack side of the film, just inside the sprocket holes on the emulsion side. It is only 1/16 inch wide. maybe less.
Brad, I'm going to the theatre and getting a clip of the film to send. -- Thanks!
My theory is that there is a small, almost microscopic pit on one of the rollers. I might put some "High Spot Ink" on the rollers one at a time and run a film loop (Old film). The ink will rub off the rollers and make any burrs or pits in the rollers turn blue. What do you guys think?
What's "high-spot ink"??? -- That's what they use in machine shops to tell if the parts that they are making are perfectly flat. It's a blue 'paste' that you spread on a straight-edge and rub on the part that you want to check. The ink transfers to the part and the pattern of the ink tells you where you have to have to remove some more of the metal. (Of course I'll be careful not to get the stuff on any parts of the proj. that I'm not specifically looking at AND I'll use old film that I don't care about.)
Posted by Brad Miller (Member # 2) on 09-08-1999, 03:57 PM:
Have you checked your pad rollers? Some of the older projectors had a little ring just inside the sprocket area instead of like the newer rollers do which only have the outer flanges to them. That would make tiny marks on the absolute extreme edge of your picture (and right analog sound track).Perform this quick test...
Grab yourself a trailer and cut yourself 3 strips of film 6-8 inches long.
Now insert 2 strips into a pad roller/sprocket and close the pad roller assembly. Does the pad roller spin freely? It should.
Now insert 3 strips and check to see if the pad roller will spin freely. It should have a bit of a drag to it.
If your pad rollers are a touch too close to the sprockets, there's your problem. It will also explain why it takes so long for the tick marks to appear.
Note: make sure to use normal film stocks from a recent trailer and not a test loop or other film stock.
As to the strip of film, just cut off a foot of it and stick it in a regular envelope. You can mail it to:
Film-Tech
9794 Forest Lane PMB356
Dallas, Tx 75243-5702
Posted by Randy Stankey (Member # 64) on 09-08-1999, 04:14 PM:
Thanks, Brad.I just got off the phone with the theatre. I'm having them clip a few frames out of the 'blue band' at the end of the print. It will be in the mail as soon as I get hold of it.
Yes, the pad rollers have that little 'ring' on them. I'll be checking them too.
Today is my day off. Not working again till Friday. I'll be checking the pad rollers the moment I get to work.
Posted by Brad Miller (Member # 2) on 09-12-1999, 01:52 AM:
Received your letter with the sample piece of film. Your problem is definitely the holdback sprocket's pad roller in the soundhead. It is too tight up against the sprocket and causing abrasion. Your other pad rollers in the projector head are fine.Might I recommend to first get yourself a small allen wrench to remove the cap from the end of the pad roller shaft. Then remove the roller itself. Closely under a light, inspect for any abrasion on the inboard "ring" of the pad roller. Somewhere on there is a tiny, tiny nick. You might be able to smooth it out with some fine grain sandpaper, but your problem will go away if you simply adjust the machine screw stop on the arm of the pad roller so that there is more clearance between the pad roller and sprocket. The ideal way to do this is 2 messages above. Remember, the pad rollers should NOT turn with film running, but be able to spin freely without so much clearance that the film can jump the sprocket. Ideally of course, you should replace the pad roller too.
Posted by Gordon McLeod (Member # 33) on 09-13-1999, 11:48 AM:
There use to be problems with a padroller used by century and simplex that didn't have a inner flange on the inboard side of the sprocket holes. Rick Long will probably better remeber for I think it was at the fairview in toronto that a similar problem was cured by changeing the pad rollers
Posted by Randy Stankey (Member # 64) on 09-14-1999, 05:33 PM:
I have checked the roller like you said. It was the holdback's pad roller. There was a little nick in it too. You really had to squint to see it but it was there, none-the-less.Went to adjust the roller and found that the shaft on that roller was bent! I guess that's why only one side of it was hitting.
If you chuck the shaft in a screw gun and spin it, you can see it wobble as it spins.
A new shaft and pad roller are on order. I've adjusted the roller as best as can be expected. (Twisting the bent shaft in its mounting hole before you tighten the set screw helped me find the best fit with the least possible damage.
It's been running since last Saturday with a new print and no damage yet.
Your help is much appreciated, Brad. I've been telling people about this site at work.
People here at TT17 are much impressed.
Thanks again.
Randy
Posted by Art Averett (Member # 367) on 09-15-1999, 03:55 PM:
Randy has the right reply. Order pad rollers from Lavezzie. The phone # is 1-800-323-1772 or fax them at 630-582-1238.