Film-Tech Forum ARCHIVE: Scratches -- need help

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

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Posted by Brandon Henry (Member # 4161) on 03-20-2007, 11:34 AM:

I have one projector that seems to be scratching the last two movies that have played. The scratches are on the left half of the screen as you look at it and are mostly horizontal but with a slight slant up to the right side of the screen. I have checked to see if the film is rubbing on the platter as it takes up and it is not.

Also I had seen a post or article about how to thread the film depending on the side of the projectors the platter reside on. While I am confident most of our booth people have been doing this incorrect on our screens where the platters are on the non-operating side of the projector I need some verification before I can go to the manager to have this corrected.

Any help is greatly appreciated.

Posted by Randy Stankey (Member # 64) on 03-20-2007, 11:45 AM:

Diagonal or horizontal scratches are very common signs of film being scratched on a surface that is moving laterally as it moves along the threading path.

Virtually the only item in a normal projector setup that moves laterally is the platter.

Another guess is that the film is slipping sideways off a roller as it goes along. Again, this is indicative of somebody doing a poor job of threading the projector and film transport system.

Without more information I can only guess but my guess is that the platter IS the problem. But, what I think is happening is that there is one person who is threading the platter incorrectly. He or she is the one damaging the film then leaving YOU to clean up the mess.

What kind of platters do you have? Christie or SPECO?
We need that information to help you better.

Posted by Christopher Meredith (Member # 3767) on 03-20-2007, 11:59 AM:

Most likely, you're looking at a cock-eyed roller. Check all the rollers, particularly the ones on casters that swivel side-to-side. Make sure they do in fact swivel with very little resistance. Also make sure you have all appropriate pad rollers (Regal calls them "keepers") in place. It's really common, particularly with Strong platters, for these pad rollers to come off leaving only the narrow plastic shaft behind. This is particularly common when there are brain wraps or other such issues which cause the roller brackets to become bent.

Posted by Brad Miller (Member # 2) on 03-20-2007, 12:45 PM:

Yup, HAVE to know your equipment brand and model to help here. If you can take some pictures of the film threaded from a few angles and upload them here that would absolutely help.

Posted by Brandon Henry (Member # 4161) on 03-20-2007, 12:58 PM:

We are using the Alpha Platters by Potts, Inc. Model 35-A3. I will try to get some pictures however I am working one day a week at the moment (used to work full time only recently returned for the pure enjoyment of working in the booth). In addition to my one day a week I was asked to help resolve technical issues as everyone else left.

It is frustrating to show up to work and have a movie that has been released for 3 days already be scratched and have no one really care about it.

Posted by Brad Miller (Member # 2) on 03-20-2007, 01:00 PM:

Check the last roller on the takeup chain for each deck. See if it rotates back and forth easily. Also check the rollers on top and bottom of the projector to make sure they are not knocked out of alignment. The film should not touch the flages of the rollers, but enter and exit the roller straight in between the flanges.

Posted by Randy Stankey (Member # 64) on 03-20-2007, 06:32 PM:

What about those two dumbass "over-the-top" rollers at the top of the tree before coming to the takeup swivel roller?

The film should go over BOTH of them when taking up to the TOP deck and it should only go over the BACK roller when taking up on the second or third deck.

If you thread to the wrong one you WILL cause scratching!

A Strong/Potts platter is FULL of trip-ups like that. You MUST thread them the EXACT way it says in the manual or you risk damaging the film.

In a theater full of bone heads, these will be common mistakes. It can also be the reason why the damage occurs some times but not others.