Film-Tech Forum ARCHIVE: Black vertical scratches

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Posted by Rob Brooks (Member # 186) on 02-17-2000, 11:17 PM:

What are some of the reasons for the light vertical black scratches you see so often after a film has been running a few weeks? Could worn, uneven and dirty platter rollers be the culprit, or are there other reasons. The public never complains, but it drives us projection people batty.

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Rob

Posted by Brad Miller (Member # 2) on 02-18-2000, 02:35 AM:

The #1 culprit is simply not cleaning the projector heads out well enough between every single show. Without knowing what type of projectors and platters you have, it would be difficult to offer anything more detailed.

Posted by John Walsh (Member # 168) on 02-18-2000, 09:29 AM:

Black colored scratches usually mean the scratch is on the base side of the film. If it's a scratch that "skips" than that's an indication it's being caused somewhere near the intermittent, or sometimes by the platter feed-out arm (as it swings back and forth). If it's continuous, than it could be almost anywhere in the film path, from platter to projector and/or back. Personally, I find that the projector almost never scratches film. It's usually somewhere on the platter or the "right-angle" rollers on the top/bottom of the projector.

Where are the scratches? In the center, or off to one side, etc.

We had a weird thing awhile ago. The on our platters (Xetron- new style) film use to just go from a platter deck straight up to the top of the platter mast. Later, we added a film accumulator (to prevent static platter wraps) to our platters. To make it work, the film now goes all the way down to the bottom of the platter mast, then back to the top. As it goes down, then back up, the film is parallel to itself with the emulsion sides facing. Static electricity was causing the two lengths of film to stick together while running. They stuck hard, too. That film did have scratches on it, but I can't say for sure that caused it. (We have too many "unknowns" here, if you know what I mean!) I meant to thread it reversed (with base sides facing) to see what would happen, but didn't get the chance. Christie' feed-out roller assembly has a nice feature where it puts a little tension on the film after the pay-out, which would probably prevent this.

Posted by Gordon McLeod (Member # 33) on 02-18-2000, 10:37 AM:

Short black scratchs are on the base and quiet often due to wrong loop size so the film is hitting only in one spot

Posted by Paul Konen (Member # 41) on 02-18-2000, 11:05 AM:

If the scratches are on the right side of the projected image and you have Christie platters, I have discovered that the scratches come from the first roller after payout. The film, for some reason, rode up on the roller toward the tree and the lovely design of the roller assembly cause the film to abrade against it. You can see this by reflecting light up from below by this roller and see the evidence on the film as it is playing.

Paul
Cinemark - Legacy

Posted by Brad Miller (Member # 2) on 02-18-2000, 02:12 PM:

Paul, loosen the bolt on top of those rollers, thread up your film and get it running (a junk trailer is enough). While it's running, determine the precise angle it should be at and retighten. Problem solved...FOREVER.

Posted by Rob Brooks (Member # 186) on 02-23-2000, 09:58 PM:

Thanks to all for your helpful information. I have Christie platters and Strong simplex projectors. 2 of my 12 theaters are 35/70 heads. What can be tough about tracing problems such as black vertical (continous) scratches is we move film around so often. It can be hard figuring out which house it was in when the scratches occured.

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Rob

Posted by Randy Stankey (Member # 64) on 02-23-2000, 10:37 PM:

Oh! I feel your pain, Rob!

We've had a lot of problems like this in the past. Problems would occur on one proj. then the print gets moved. It can be a nightmare!

My advice is to try to figure out if it's caused by "operator error" or "equipment problems"...

First, do you have any kind of record keeping on where prints were in the past? I use the trailer lists we have to keep as a kind of "history" log. If there's a problem I can just look back and see what houses that print has played in for the last few weeks. Problem is that you have to spot a pattern. That might mean that you'll have to scratch a couple of prints.

Second, at Cinemark we have to sign off on a checklist for every movie we start. That way you can see who ran a particular show when a problem occured. People don't like to do it at first but if you tell them they have to or face "discipline", it'll become a routine thing after a while. Again, patterns will start to show up. For instance, if "person X" works on Wednesday nights and a problem always seems to appear on Thurdsay morning you can make a pretty good guess who's messing stuff up. Then you can supervise that person more closely and "correct" the situation.

At Tinseltown (Cinemark) we were lacking in the presentation department for a while, despite the fact that we had a couple of really good people. We enacted a "Presentation Improvement Program" (Affectionately known as P.I.P) Since this summer we have improved things 1000%. (We also got rid of a lot of "dead wood" if you know what I mean. ) We went from several wraps a week to zero. We are now averaging 1-2 interruptions per month (for ANY reason, including malfunctions) when we used to have them almost daily.

Finally... Get FilmGuard! It will minimize ,if not eliminate, those fine scratches!