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Topic: Horizontal Scratches

Tom Kroening
Expert Film Handler

Posts: 214
From: Janesville, WI USA
Registered: Oct 1999

posted 05-13-2000 04:40 PM

We're having a slight problem with horizontal scratches on a few prints. We're using Christie equipment (fairly new P35's and AW3's). Mostlikly its operator error, but what sort of error would result in horizontal or ner horizontal scratches? Rubbing against the platter would cause diagnal scratches... Can anyone help out? Thanks.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-13-2000 04:44 PM

Sitting on top of a roller causes a diagonal slash mark

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-13-2000 04:48 PM

OH, OH, OH, OH, ME, ME, ME, ME, ME, PICK ME!

Let's see Christie projectors and "not horizontal" but "not diagonal" scratching? Are these dash type scratches not extending from side to side and "almost" horizontal"???

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Tom Kroening
Expert Film Handler

Posts: 214
From: Janesville, WI USA
Registered: Oct 1999

posted 05-13-2000 05:39 PM

Yep, those would be the ones Brad, any ideas?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 05-13-2000 06:22 PM

>>"We're having a slight problem with horizontal scratches on a few prints.
We're using Christie equipment (fairly new P35's..."<<

Using P-35s? Then you have more than a slight problem ;-) Just couldn't resist!

Ahem....now back to our feature presentation, already in progress....back to you Brad!

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-13-2000 06:30 PM

This one is all too common. You are making your lower loops too big. Christie now makes a bracket that attaches to the underside of the Ultramittent to prevent this, but I have no idea on cost.

Anyway, after you thread your projectors, open the pad roller right below the Ultramittent and turn the machine over by hand. The film should just barely tug on the open pad roller. If it is any bigger, you WILL scratch the film in that manner.

It's as simple as that.

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Tom Kroening
Expert Film Handler

Posts: 214
From: Janesville, WI USA
Registered: Oct 1999

posted 05-13-2000 08:10 PM

Hey, thanks alot. We'll just have to retrain a few people. : )

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Paul Konen
Jedi Master Film Handler

Posts: 981
From: Frisco, TX. (North of Dallas)
Registered: Jun 99

posted 05-15-2000 08:40 AM

We had the same problem when loading to the bottom platter. The operator didn't rest the takeup platter selector (on the tree) on the bottom pin but at the very bottom and this caused nearly perfectly horizontal scratches across the entire frame.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 05-15-2000 12:31 PM

Just had this problem in one of my theatres. Turned out to be the film riding up on a roller, as Gordon noted.

------------------
Better Projection Pays!

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Mike Blakesley
Film God

Posts: 12767
From: Forsyth, Montana
Registered: Jun 99

posted 05-15-2000 12:39 PM

I was in a booth once where they used a home-made plywood deal to move prints. It was a 3/4" thick donut of plywood. They would put that on the platter, run the film onto it and clamp it. Problem was, they didn't adjust the height of the rollers, so the film would drag across the edge of the plywood. Result = scratches. This was about 10 years ago, hopefully they don't do this any more.

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 05-15-2000 01:26 PM

When trouble-shooting film scratches, look at the entire film-handling system: from print inspection and rewinding, to make-up, to platter feed, to projector and soundheads, to platter take-up. ANYTHING that touches the image area of the print is suspect. Once you imagine yourself "in the film's place", the source of the scratches (rubbing on the platter surface during make-up, misaligned guide roller, excess tension on an undercut roller, wrong loop size) is usually obvious.

Base side scratches are usually black (the scratch scatters light). Very superficial emulsion side scratches show as black, but deeper emulsion-side scratches are green, yellow or clear (depending on how deep they penetrate into the colored dye layers).

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 05-15-2000 03:36 PM

Note to Christie R&D team: extend the lower end of the AW3 takeup bar another several inches to make it incredibly obvious when the cluster is not seated on the bottom peg.

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