my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Perforated Scratch. Please help (Page 1)

This topic comprises 2 pages: 1  2

Author Topic: Perforated Scratch. Please help Jack Terrell Film Handler Posts: 7 From: Atlanta, GA, United States Registered: Apr 2011 posted 04-24-2011 09:02 PM                     I am having a very annoying scratch problem. One of our projectors (simplex 35 and 5 star sound head) is putting a vertical scratch down the left of center of the frame (with the sound line that is actually about the center of the film). The scratch is white-ish and it is intermittent - meaning it looks like a perforated line cut on a piece of paper. The scratch takes about a week to show. My first thought is that it is a roller or sprocket 'poking' the film at every revolution. Although, rollers aren't suppose to touch that part of the film, and all of the rollers seem in fine condition. In fact, I recently cleaned or replaced all of the rollers on the christe autowind 3. I did this when I first became projection manager at this location, and the scratch may have coincided with the cleaning.... because no one noticed the scratch before. If anyone has seen this before, please help!! a quarter of my prints have this scratch now! The only option i see is to replace each roller/sprocket one by one and wait a week to see if the print scratches....  |  IP: Logged Stephen Cattenazzi Film Handler Posts: 14 From: Mernda, Victoria, Australia Registered: Feb 2004 posted 04-24-2011 10:52 PM                        We had something similar where I am (although different equipment). I actually found a piece of splicing tape had come off the film, and got stuck onto the bracket holding the top feed roller leading to the top of the projector head. I'm not familiar with your equip. so this might be pointless for you. But thought it might be worth a mention.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 04-25-2011 12:17 AM                     White scratches are usually emulsion side scratches. This theoretically eliminates pad rollers but it leaves the possibility of the problem being caused by any of the four sprockets or the sound drum. Go down through the projector's film path, one piece at a time and inspect for problems as you go. (Be the film.) I'm going to ask a wild-ass question: Do you clean projectors with a toothbrush? It is common for bristles to be pulled out of the toothbrush and get caught in the projector sprockets. Every time the sprocket makes a rotation, that piece of bristle slaps against the film and, over time, makes marks. Another place where problems can happen is on the sound drum. If a piece of crud gets on the drum (or on either of the metal film rollers in the sound head) it can cause scratches. Third thing to look at is to make sure everybody who uses the projector is threading it correctly. If you make your bottom, intermittent loop too large it can slap against the back of the projector bulkhead and cause scratches. The reason why it seems to take a week to appear is because only one person is making this fuck-up. It might pay you to go through your employee schedule and see if you can correlate your scratching problems with one particular person's shifts. You do keep a booth log book... Don't you?  |  IP: Logged Jack Terrell Film Handler Posts: 7 From: Atlanta, GA, United States Registered: Apr 2011 posted 04-25-2011 12:37 AM                     Thanks for your reply I have inspected the four sprocket, pretty closely, maybe I should get out my magnifying glass... The boothers used tooth brushes before i got there. I switched em to metal bristles - which could be worse... I will look for that. Its hard to get a good look at the sound drum and lateral guide roller, but i will look closer. I have been focusing mostly on the rollers that I replaced. I have noticed that others loop their lower intermittent loop too big, but I have isolated this to only prints that spend time on projector 2, so unless there is something on that bulkhead wall when it slaps, I don't think that it is the problem. But it could be other threading issues, like incorrect damper tension, which could cause the film to pull against the sprockets and maybe cause contact in the center part of the film, especially on the sound drum, which is right above the damper roller. Perhaps farfetched. I also noticed that one of the pad rollers does not turn freely with the film. ?  |  IP: Logged Chase Pickett Expert Film Handler Posts: 142 From: Irving, Texas, USA Registered: Nov 2010 posted 04-25-2011 12:38 AM                     There are two things I think could be the problem. First, check the pad roller on the 5 star sound drum, and make it as clean as possible, no matter what it takes. In fact, I would recommend the tip for eliminating that rubber pad roller all together. It's named "how to make a simplex 5 star sound head more film friendly" under the tips in the warehouse. Second, make sure the lateral guide rollers right above the film gate are spinning properly, if not the film could be bending toward the film gate scratching the film ever so slightly and intermittently. Clean and lube if needed. Actually just clean and lube it anyways. Couldn't hurt right? Hope this helps -Chase  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 04-25-2011 01:07 AM                        Do you have any fairly tight twists in your film path? I wasn't getting quite what you describe, but a looong time ago I was getting green specks in the formation of a line left of center after a print played in an auditorium for a while. The twist coming out of the bottom of the sound head going to the lower magazine roller was too extreme, so I made sure it was as relaxed as possible. No more scratches in that auditorium, ever.  |  IP: Logged Jack Terrell Film Handler Posts: 7 From: Atlanta, GA, United States Registered: Apr 2011 posted 04-25-2011 01:21 AM                     That does sound like what I'm getting. They are green or white - clearly emulsion side. It twists a little coming off the failsafe to the first roller, but not too extreme.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 04-25-2011 01:28 AM                        Straighten it out as much as you can and see what happens to future prints after they have been in that auditorium for a week or two (it usually took a couple of weeks for the scratch to show up on mine). Ideally, the roller will be directly underneath the roller where it comes out of the failsafe, not angled forward or back. If you can't do this, just try to make it as nice as possible.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 04-25-2011 08:47 AM                     I hardly use any brushes. I use a soft bristle paint brush to occasionally clean in hard to reach areas but 90% of the time I just use a shop rag to clean the inside of the projector. But I also use FilmGuard 100% of the time so projector cleaning is greatly simplified for me. I wouldn't ever use a metal brush inside the projector. Yes, check the damper arm and roller in the sound head. I sort of just assumed that was understood when I was talking about the sound drum. (Telegraphic language... )  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 04-25-2011 09:13 AM                        I think you may have Strong or Potts platters. If so, someone missed one of the rollers on the up/down carriage. The "left of center" mark is made by the edge of the small plastic or metal button in the carriage. East to prove; make a loop of newer junk trailer and deliberately misthread. Look for increasing damage. Louis  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 04-25-2011 10:26 AM                     If this will help any, I posted this back in 2006 .. see what you think and good luck in finding the scratching issue - Monte Perfect threading  |  IP: Logged Jack Terrell Film Handler Posts: 7 From: Atlanta, GA, United States Registered: Apr 2011 posted 04-25-2011 12:24 PM                     So here is what i did, and I will let ya'll know if the print that just got put in there is scratched in a week or two. The twist coming off of the failsafe to the lower roller was more extreme than i thought. it was causing the film to awkwardly position itself to the two rollers, which caused light contact of the non-edge parts of the film. The next thing I did was remove a ton of plastic fibers from the lateral guide roller on the sound drum. They were wrapped around the roller, between the friction roller and the outboard assembly piece of the roller. there were about 20-30 pieces, and they were about 1-2 inches long; white nylon? And many were slapping against the film or stuck to the surface of the friction roller - which by the way I do want to do that mod to replace that stupid thing!. I cant imagine where these pieces of fiber came from. They seem like nylon. They're too big to be tooth brush fibers. They did vary in length. perhaps they're strand of nylon that peeled off of the pad roller that doesn't spin freely - it is right above this assembly. Must replace/lube asap. My money is on the fibers. But we'll see in a week or two. Thank you so much for your help guys!  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 04-25-2011 01:25 PM                     Yup, its that stupid soundhead design coming back to damage more prints. I said "that's the stupidest design ever" back when I first saw it on an RCA "boat anchor" soundhead eeons ago and I still feel that way to this day. The prints that damn thing is scratching will probably be the ones randomly selected to keep for repertory shows at the depot too. Even if somebody at the depot cared to look at the print, the damage those rollers cause are usually very difficult to see without being projected. Someone will undoubtedly come on after me whining that the design is wonderful and the operator isn't keeping it clean, but regardless the design is stupid because it forces people to keep them perfectly clean all the time, and with platters running a couple of miles of film through the soundhead at one time, the embedding of dirt is pretty much a given. Case in point, when I first started to work at the UA Berkeley in 1993, their projectors had not been cleaned since they opened in 1986. Seriously. There was so much gunk caked onto the sprockets that the teeth were BARELY discernable sticking out from the hardened dirt. They had 7 Simplexes and 1 Century. The print on the Century had been running for 2, maybe 2.5 months exclusively in that auditorium and other than dirt buildup at the reel changes looked essentially new. All of the other prints (ran on those damned Simplex soundheads) were essentially unwatchable even in the middle of the reel. Even a print they had only been running for ONE WEEK looked terrible. Sure that is an extreme example, but it does prove how awful the Simplex/RCA soundhead design is.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 04-25-2011 07:13 PM                     Remember, toothbrush bristles are twice as long as you think they are. Toothbrushes are made by embedding the middle of the fiber into the plastic handle then cutting off the brushes so they are even. Each single bristle is actually kind of shaped like a letter "V." When bristles pull out of a toothbrush they'll be 1-1/2 or 2 inches long. This problem will go away if you stop using toothbrushes to clean projectors. Use a red shop rag and do it EVERY time you thread the machine. If done conscientiously, you will not need to use a toothbrush because your projector will always be clean. You will only need to do major cleanouts once or twice a week, depending on the amount of film you run. In a 20 screen theater where I once worked, there was 1 guy per shift on weekdays and 2 guys per shift on weekends/holidays. We had a rule, each person had to do a full cleanout of one projector each shift. If everybody held up his end of the deal, each projector got a full cleaning once per week. As long as projectors got a wipe every time they were threaded, no more work was needed but, if people started getting lazy, projectors would get filthy in no time at all. By the time the end of the week rolled around, they were full of dust and the rails were all covered in baked on crap. My advice: Toss out the toothbrushes and keep, maybe, one or two on hand in the supply cabinet for use when you need them. If you use FilmGuard on every show, you can even skip a cleaning and the projectors will still look good and run well!  |  IP: Logged Jack Terrell Film Handler Posts: 7 From: Atlanta, GA, United States Registered: Apr 2011 posted 04-25-2011 07:31 PM                     Maybe I should start a new tread for this, but in keeping with the last coment, what is the best recommendation to clean out a not so well maintained projector. The components, for the most part (present discussion excluded) are cleanish, but the walls and hard to reach areas are covered in a wetish oily gunky stuff. I'd love to just wipe it out, but it's hard to reach. Would you all suggest just getting what I can, or actually removing components and wiping the walls?  |  IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1  2

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.