Film-Tech Forum ARCHIVE: Horizontal Scratches

This is topic Horizontal Scratches in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ken Lackner (Member # 1002) on 09-27-2003, 10:53 AM:

I noticed that one of our prints has light black horizontal scratches toward the edges of the picture. They are not diagonal like platter scratches. What could causes this?

Posted by Paul G. Thompson (Member # 655) on 09-27-2003, 12:40 PM:

Are they film stock scratches or emulsion scratches? Do the scratches get into the picture area?

Posted by Kenneth Wuepper (Member # 1174) on 09-27-2003, 12:49 PM:

Ken,
I need more information on these "scratches" which are black on the screen. Or, are they black on the film itself?

When I was processing film in a very dry darkroom there was a problem with static discharges making dark streaks on the edges of the film which showed up after it was developed.

Is this streaking found in all reels or just a few? Or just one?
Scratches on the emulsion side show up as lighter and often colored streaks until the entire emulsion is abraded then they are white (clear). Base scratches tend to show in the screen as darker areas or as black streaks. Both of these scratches can be seen with the naked eye or with a magnifier lens.

KEN

Posted by John Pytlak (Member # 331) on 09-27-2003, 01:34 PM:

Could still be "platter scratches" if the abrading rough spot was at the very outside of the platter, such that is moved almost horizontally across the film. Could also be cinch marks caused when flattening a unevenly wound or loose wound roll of film.

Posted by Chris Hipp (Member # 1788) on 09-27-2003, 02:07 PM:

I have had scratches like this on the right hand side onf the screen. It was usually cause by the film riding on the support bar for the lower magazine roller. Check to see if that is tight.

Posted by Ken Lackner (Member # 1002) on 09-27-2003, 02:16 PM:

I do not know if the scratches occur during the entire film or just one reel. I just happened to notice them when I was walking theaters. They probally are base side scratches since they are black. Could be from flattening a roll of film as John mentioned.

Posted by Michael Schaffer (Member # 1204) on 09-28-2003, 04:33 AM:

What do you mean by flattening?

Posted by Steve Kraus (Member # 476) on 09-28-2003, 09:27 AM:

He means if the film has wound unevenly, say a few turns have wound with the bottoms higher than the platter deck, and if it's loose enough or slippery enough after treatment, that someone would push them down to even it out. Similarly with film on a reel if it's wound unevenly and the reel flanges get pushed together. In these situations the film layers will slide horizontally against each other and the possibility of scratching exists.

Posted by Scott Norwood (Member # 30) on 09-28-2003, 10:45 AM:

Did the print come from a changeover house? It sounds like the damage that others have described (loosely wound print).

Posted by Brad Miller (Member # 2) on 09-28-2003, 02:23 PM:

Your platter make/model?

Your projector make/model?

Emulsion or base side?

"Toward the edges of the picture"...you mean both sides? Please be specific. Toward the soundtrack edge (left side of screen)? Picture edge (right side of screen)?

Are you absolutely sure the scratches are perfectly level/horizontal and don't have the slightest diagonal angle to them? If there is a slight angle, which direction is it as projected on the screen?

Find out if the scratches exist from reel 1 of the movie to the last reel. Does the angle of the scratch (if any, see above) change during the movie?

Do you run soundtrack up or down on your platter at your theater?

Was the print new when you received it?

We need to know that info. Otherwise this thread will become a place for everyone to just report things that caused scratches for them in the past.

Posted by Ken Lackner (Member # 1002) on 09-29-2003, 12:30 AM:

What I don't know, I'll try to find out next time I work.

TECO platter.
Kinton FP-23C projector.
Don't know if emulsion or base side. Will find out.
Yes, both sides, but not in the center of the picture.
IIRC, completely horizontal.
I will find out.
Soundtrack up.
Pretty sure the print was new. Will find out.

Posted by Adam Martin (Member # 641) on 09-29-2003, 01:43 AM:

quote:
Yes, both sides, but not in the center of the picture.

What are the humidity and temperature conditions in the booth?

Posted by Gordon McLeod (Member # 33) on 09-29-2003, 10:31 AM:

On the Tecco platters in particular check for one of the rollers not turning
They are rather sloppy in there width tolerances at best and can cause funny scratchs if they are not freely turning
Also I have seen the odd DTS reader that has induced light base scratches at the sides for no apparent reason