Film-Tech Forum ARCHIVE: Horizontal Scratches on both side of Perforation

This is topic Horizontal Scratches on both side of Perforation in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Peter John Anthony. C (Member # 2500) on 11-24-2007, 09:04 AM:

Hi!!
Required your advice, since 2 weeks i am facing this problem in all print.
After 4 to 5 days of print run i can see Horizontal scratches which starts from outer edge of film through the perforation toward the image area about 1.5mm. Due to this problem D.Digital fails, when sound reverts to SR we hear hissing sound.
We have strong projection system which is 6 years old... Projector Head--- Simplex,Sound Head 5-Star, Strong Platter & Make Up Table...
Awaited for your valuable advice to rectify the same.
Regards,
Peter.

Posted by Richard Fowler (Member # 893) on 11-24-2007, 11:47 AM:

Pressure bands in the picture gate may need to be adjusted or replaced.

Posted by Ron Funderburg (Member # 4561) on 11-24-2007, 12:05 PM:

Are the scratches horizontal straight across or lateral at an angle across the film? Straight across indicates scratching that it is occurring in the gate while film is at rest and lateral is when the film is traveling. Most common place for this to happen is going on to the platter!

Ron

Posted by Bernie Anderson Jr (Member # 410) on 11-24-2007, 06:40 PM:

I've never heard of horizontal scratches coming from the gate. How so? Its rare to see perfectly horizontal scratches, I've seen them but not often.

Posted by Ron Funderburg (Member # 4561) on 11-24-2007, 08:15 PM:

Bernie,

I agree it is rare and I have no idea if it is happening in the gate or elsewhere but the gate is the only place you don't have continuous movement so it would seem to me it would be the only place that a perfectly horizontal scratch could happen. I have one theater that was doing some always at the end of the movies not all the way though we took the gate off and cleaned it good and haven't had them sense.

I still can't see how film not moving can get scratched and if the film is moving it would seem to me that it either has to be lateral or vertical. Lateral is almost always on the platter usually from people running the film with sound track pointing down.

Ron

Posted by Bernie Anderson Jr (Member # 410) on 11-24-2007, 11:17 PM:

I've seen horizontal scratches happen in XLs when the bottom loop is too big and hits the back of the projector housing. I usually get it when people are training. That XL loop has to be right on the money.

Posted by Scott Christopher (Member # 834) on 11-25-2007, 03:44 AM:

Check the film height where it returns to the platter.

Posted by Chris Slycord (Member # 4239) on 11-25-2007, 04:06 AM:

Platter would be my guess as well. At least on the strong platters I'm using, when the film comes off the last roller onto the platter it starts out almost perfectly flat where if the roller were too low both perforated sides would hit the surface of the platter.

Posted by Cameron Glendinning (Member # 3516) on 11-25-2007, 04:02 PM:

quote: Peter John Anthony. C
sound reverts to SR we hear hissing sound.

Does your projector need a red light reader? SR can sound almost as clean as digital in ideal conditions.

Perhaps if you place some red gel over your white light exciter and raise the levels, you will decrease the amount of hiss, when it fall back to sr.

Posted by Richard May (Member # 2627) on 11-25-2007, 07:54 PM:

This problem drove me crazy for the longest time. Mainly because they were perfect horizontal scratches in a short area on both sides of the film. The problem happened only on simplex projectors. Both times the problem turned out to be the intermittent shoe on the bottom of the gate. There was enough play back and forth from the shoe that it would bounce from side to side and scratch the digital area and the optical soundtrack. Both times I replaced the shoe and it immediately stopped scratching.

Posted by Scott McGuire (Member # 4508) on 11-26-2007, 12:34 AM:

We were having this problem a few months back and it turned out to be a loose roller on our platter. I think i found out to look for this somewhere in this forum can't remeber where thought.

Posted by Marin Zorica (Member # 1716) on 11-26-2007, 04:11 AM:

Yes I notticed this strange scracthes this summer. On start of projection in open air cinema where we use only analog I notticed some pop's in sound, but quite small, I was think some of speaker driver left...then I notticed straches from sound side of film thru center of picture....

This wasn't done by "us" it was done by cinemas which played film firts.

Posted by Peter John Anthony. C (Member # 2500) on 11-26-2007, 12:29 PM:

Thanks a ton for all the advice...
The scratches seen on film edges are horizontal.
We have changed all the Platter black roller...
Now option to try are...
1) Gate alingment.
2) Will replace Pressure band.
3) will replace the Shoe pad.

Will update the same once done the above, mean time more helps are awaited...
Thanks,
peter