Film-Tech Forum ARCHIVE: SCRATCHS...HELP!!!

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Posted by Robert Edgecomb (Member # 2335) on 04-25-2004, 11:01 AM:

I am hoping that someone can help me. I run a 6 booth art house and I have Simplexs in all the booths. It is occurring that in at least 3 of the prints playing there are horizontal (usually alittle diagonal as well) scratches running down the middle of the film. I have no idea what would be causing this. I have a sneaking suspicion it is the lateral guide roller but I honestly don't know.

I really hope someone can help. I am doing what I can but I still don't know how to stop it.

R.

Posted by Robert Stawiarski (Member # 1842) on 04-25-2004, 11:29 AM:

Have you checked the take-up roller on your platter system?

Posted by Robert Edgecomb (Member # 2335) on 04-25-2004, 11:52 AM:

I have checked all of the rollers to make sure that they never touch the middle of the film (which is where to scratches are, they are only in the middle).

Posted by Chris Hipp (Member # 1788) on 04-25-2004, 11:55 AM:

Watch the film as it goes onto the take up platter and see if the platter hits the film at any point. Also, watch all rollers during the show, if the film comes off a roller and rides on the side of a spinning roller it will cause lateral scratches.

Posted by Robert Stawiarski (Member # 1842) on 04-25-2004, 12:01 PM:

Agreed. If the scratches take up most of the width of the film, it is probably due to the film in contact with the takeup platter. If the scratches are in the center and are relatively narrow, it is probably due to riding on the edge of a roller. Sometimes the film will look fine upon starting, but a splice may make it ride a roller (one of the more common places is the top roller on the projector; not the feed roller, but the top roller below the feed roller.)

Posted by Dominic Espinosa (Member # 2122) on 04-25-2004, 12:06 PM:

That certainly sounds like a roller. Also check for debri and such on any guides on your platters centerfeed ( i don't know what kind you have, but Christies like to get filthy right in front of the rollers ).
I know this sounds stupid, but...How big are your bottom loops? I had problems with this when a new projectionist made his loops entirely too big and they'd slap the bottom of the case leaving ugly short scratches all over the place.
Good luck, let us all know what it was. I know I'm currious.

Posted by Robert Edgecomb (Member # 2335) on 04-25-2004, 12:08 PM:

I am off to work now so I will check all of those things.

As far as the rollers go, I am not sure how a roller could do that. There are many scratches on a frame. They are horizontal but go down a line in the center.

Thanks for your help and I will see what else I can find.

Posted by Will Kutler (Member # 770) on 04-25-2004, 12:11 PM:

Also check for any debris in the gate/trap assembly, as well as the intermittent sprocket.

Posted by Thomas Procyk (Member # 1170) on 04-25-2004, 12:32 PM:

Robert: Do the scratches look like a narrow "drizzle" of slashes in a straight line, like this:

\
\
\
\
\
\

About that wide, too? What kind of platters are you using? I had this problem on Strong platters with their cheap little bearing rollers. If the bearings aren't good or rusted (as was the case with this horrid booth I was at) then it could be that the roller isn't spinning as fast as it should, dragging on the film just enough. (You'd hear the roller "buzzing" just a bit) I noticed those rollers aren't bevled inward too well, either. But you said you checked all the rollers, so I'm confused.

Don't know if it was this or something else, but replacing that roller made the "drizzle" scratches go away on that house.

I see these kinds of scratches on a lot of used prints we get (and reject!) second run. I'm curious as to how they're caused?

=TMP=

Posted by Darryl Spicer (Member # 711) on 04-25-2004, 12:34 PM:

Check for crack in the rubber damping roller on the sound gate. If cracked bad enough they can leave horizontal sinch marks on the middle of the film.

Posted by Ian Price (Member # 14) on 04-25-2004, 12:46 PM:

Sounds like a platter scratch to me. I would institute a program whereby the operator must check each roller after they start the film and sign off a sheet that you have done so. Or have the manager check the projectionist's thread after starting.

Even our very experienced manager missed a roller on our platter's take-up and Ky caught it and called him back up to correct it. Thankfully no damage was done to the film.

You should never walk past a platter without visually checking it.

Posted by Gordon McLeod (Member # 33) on 04-25-2004, 02:11 PM:

Often it is caused by the ilm riding up on the flange of a roller and the film then folds slightly against the spinning roller leaving the marks
all it takes is one roller misthreaded once for it to happen

Posted by John Pytlak (Member # 331) on 04-25-2004, 04:14 PM:

I agree. Either a "platter scratch" or mispositioned roller.

Platter scratches are caused by the rotating takeup platter rubbing across the surface of the film --- be sure the film is properly guided onto the platter without it "flattening out" against the rotating platter surface.

Or the film rode up onto the flange of a roller. Check all rollers to be sure they are positioned properly, so the film doesn't tend to ride up on one side.

Posted by Mark J. Marshall (Member # 1409) on 04-25-2004, 11:14 PM:

We had a problem with out Strong Alpha platter system where the last roller on the path to the take up platter, while spinning fine, would not swivel freely. So the film would stay on the roller perfectly fine, and the roller would spin perfectly fine, but it always pointed toward the center of the print directly at the edge of the take up ring, and wouldn't swivel out as the print got bigger. This caused the film to start to take a weird twist coming out of that roller on its way to the rest of the print on the take up platter. That twist caused the film to touch - and eventually get scratched by - the take up platter.

Keep checking and re-checking that roller while the film is running, but DON'T TOUCH IT! Just watch and see what happens. Especially towards the end of the film. Of course you have to check that roller on all three (or however many disks you have) platters.

There aren't many places where something runs perpendicular to the film path across the base side of the film... which is what's required to create a horizontal or diagonal scratch. That's why everyone keeps saying to look there.

Good luck, and let us know what you find!

Mark

Posted by Mike Babb (Member # 1379) on 04-25-2004, 11:28 PM:

Robert, are these scratches happening when/after the films play or is it possible they are being scratched when loading film on the platter from the make-up table? I once found someone was so worried about film riding too high on the center ring that they had dragged it across the edge of the platter loading it and caused the type of scratches you describe. It was only on the prints this specific person had put together.

Posted by Carl Martin (Member # 1146) on 04-26-2004, 02:38 AM:

i have a hard time seeing how a roller would cause horizontal scratches. if the film is riding a flange the scratch might pulsate as the film slaps against it, or if there's a burr or something on the roller. but how would the scratches be horizontal unless the film is madly shaking back and forth as it rolls over the flange?

just yesterday i did see similar scratches at another theater. horizontal hashmarks about 1/3 from the right side of the screen, bouncing up and down the image. they seemed too short and too narrowly positioned to have been platter scratches. sorry, i didn't ask them how they did it.

quote: Darryl Spicer
Check for crack in the rubber damping roller on the sound gate.

if you can figure out which projectionist is smoking crack in the booth, that would be a good start.... sorry.

carl

Posted by Chris Hipp (Member # 1788) on 04-26-2004, 08:29 AM:

A roller can very easily make lateral scratches on a print. The film isnt ridong ON the flange, it is completely OVER the flange, not moving and the roller is spinning hitting the center of the frame, just like a platter would scratch it.

Posted by Dominique Replogle (Member # 2387) on 04-27-2004, 05:21 PM:

It is the least likely cause but check your ptr's and make sure there is not a big fat peice of grit embedded in one of em.
Good Luck.

Posted by Robert Edgecomb (Member # 2335) on 04-29-2004, 01:02 AM:

Sorry to take so long to get back to you but here is the deal. They are horizontal/diagonal scratches that go down the length of this film and appear multiple times in a frame (maybe 10-15). I think it is somehow opperator error being it has appeared on 3 of our 6 prints (2 of which have played in the exact same projectors the entire time.) As well, for one of those 2 prints, we ran a screening in one and the print is fine. So I think it is an opperator, being i cannot be there 24/7, as much as I wish I could. I think it is being caused by the bottom loop, where as someone else thinks it is occurring in the center feed control. And ideas?

Posted by Brad Miller (Member # 2) on 04-30-2004, 02:34 PM:

Robert, if you want this problem solved, you have got to tell everyone here what kind of equipment you are running. Simply telling us a brand name of projector you have doesn't help much. What MODEL Simplex do you have? Also you have got to tell us what make and model platter you have since the majority vote here is that this isn't happening in the projector. Until you provide these details, you are doing nothing but wasting bandwidth and everyone's time trying to guess your situation.

Posting a picture of the scratches would be very helpful as well if you have access to a digital camera. Also, do you run soundtrack up or down on the platter? Are the scratches on the base or emulsion side? You said they are not horizontal, but close to horizontal. Are they top left to bottom right or top right to bottom left? Details, details, details.