Film-Tech Forum ARCHIVE: Small Diagonal Scratches

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Posted by Sally Ann Burgess (Member # 4746) on 08-24-2010, 02:11 AM:

We have damaged two prints in the last 6 months exactly the same way but I am really puzzled as to how they happened.
The scratches are on the emulsion side and during dark scenes there is the odd fleck of green. We use Kinoton Fp30 projectors and AW3 platters and we thread soundtrack side up on the deck.
I tried to replicate the scratches today by misthreading a trailer every way I could think of. The angle of the scratches tells me it has been dragged across a roller but I couldn't make those scratches. They look like this.....

Posted by Pete Naples (Member # 761) on 08-24-2010, 02:50 AM:

Are they slightly curved?

In my experience, scratches caused by being slightly off a flanged roller, or dragging across the edge of the take-up platter deck look a like that, but often have a slight curve to them.

Scratches across the film like that, I'd be having a look at the adjustment of the last guide roller before each take-up deck, usually it's pivoted (I'm not 100% familiar with the AW3, haven't seen one for 10 years), if the roller is too low or can move out of position, the film gets dragged over the edge of the deck as it turns. I've seen it happen that way a few times on Strong platters.

Posted by Manny Montes (Member # 5639) on 08-24-2010, 03:36 AM:

definitely sounds like platter scratches, are your platters warped to the point that the film may be bouncing against it as it takes up?

Posted by Joe Redifer (Member # 3) on 08-24-2010, 03:58 AM:

That is 100% a roller scratch. Likely the roller on the take-up arm on the Christie (the one under each deck) got twisted as the film rode over it. Not twisted enough so the film would fall off, stop the platter and the movie, unfortunately. I have never seen this happen personally, but that is really the only way is CAN happen on a Christie if it was emulsion scratches.

It can also happen on a Strong platter with the roller that leads straight on to the take-up deck, slightly cocked inward. I can't duplicate it, either, but it is the only way possible. I have an assistant manager who has done this. The film eventually falls off the roller as the size of the roll on the take-up deck grows and the emulsion scratches stop at that point. Not sure how he does it, but he has done it twice. Both times he told me the movie stopped before the credits for some odd reason and sure enough, so do the scratches.

Posted by Darryl Spicer (Member # 711) on 08-24-2010, 10:38 AM:

Joe is correct and unfortunately I have seen it happen when I have come in to run the booth and discover that the person before me was an idiot and did not check the rollers like they have been shown and told a thousand times. Breath.....Breath.....oh that said person no longer works in the booth.

Posted by Joe Elliott (Member # 4006) on 08-24-2010, 01:04 PM:

Same here, I agree take up arm roller scratch. We had a kid that would thread up forward, and when he would pull the film up to activate the take up, he would then let the film from his hand drop. Try it, 3 out of 4 times the take up roller will turn at an angle. He would of course never check his rollers. It was not long before we replaced him.

Posted by Monte L Fullmer (Member # 2797) on 08-24-2010, 04:12 PM:

Yep, good ol' AW3's love to make them if the film isn't tracking in the rollers correctly.

Check any of the tension areas in the film travel ..

quote: Joe Redifer
the roller that leads straight on to the take-up deck, slightly cocked inward

, plus, if you have a brain wrap, the roller spindle will be slightly angling up since the bracket that the spindle is mounted on gets bent up due to this wrap. If you got a roller that isn't close to that keeper, bet the bracket is bent.

Good luck - Monte

Posted by Sally Ann Burgess (Member # 4746) on 08-25-2010, 01:46 AM:

Thanks for your input gents.
Manny, I'm 100% certain they are not platter scratches...the action is fairly low between the film and the platters on that particular deck, but the scratches would be on the base side...and the scratches would be a lot wider I think, and not at such an angle.
Oh well, something else to add to the "Scratches" section of my Procedures Manual!!
Cheers all.

Posted by Manny Montes (Member # 5639) on 08-25-2010, 03:10 AM:

totally right, I guess i breezed right past the part that said "emulsion scratches" and just looked at the black lines on your wonderful diagram

Posted by Brad Miller (Member # 2) on 08-25-2010, 05:42 AM:

Check Joe's post above. It is most likely as he describes, although I must admit like himself, I find it quite difficult to get the film to sit crooked and dragging partway around that roller on the takeup arm, but it IS possible if you get it misthreaded just right.

Posted by Sally Ann Burgess (Member # 4746) on 08-25-2010, 07:06 AM:

Brad, I was actually able to misthread incorrectly around the take up roller but it was pretty hard to do...it either just slipped back into place or off altogether. And I couldn't see any scratches when I DID succeed in doing that!
I know now that it must have been that, but I'm determined to cause those scratches on an unused trailer to see for myself. It just seems so hard to do!

Posted by Joe Redifer (Member # 3) on 08-25-2010, 12:31 PM:

You won't be able to see the scratches until the next pass. I'm wondering if Joe Elliot is onto something, it might have to do with the way someone pulls the takeup for tension when threading from the projector. I always do this with Christies (Strongs, too), but I never just let it drop or free-fall.

Posted by Monte L Fullmer (Member # 2797) on 08-25-2010, 12:48 PM:

Since I have AW3's, the area of possible scratching is in the brain itself.

Since you got two rollers with tension springs underneath to press the film onto the middle roller, this creates the rear roller to actually "feed" the film around that center roller.

What I found is that if one doesn't pull the film through the brain tight enough when lacing through the rollers, the film will actually "loop" around the center roller-not even in contact with the outer flanges of that center roller due to this even pressure from the two outer rollers.

And with this film "looping" it's actually curling a bit where it will rub against the face of one of those tension rollers.

Some ideas to throw out .. - Monte

Posted by Sally Ann Burgess (Member # 4746) on 08-25-2010, 03:52 PM:

I've trained my guys to pull the film for tension BEFORE lacing the lower constant feed sprocket, never just to yank it. Not because I thought the film would get scratched on that take up arm roller, but because we used to lace the sprocket and THEN pull for tension...one day I did that and for some reason the take up arm kept coming in and in. I didn't react in time and the whole roller snapped off.
Yep, Joe's onto something there! It's just a bit disappointing when I've also hammered into staff to check constantly that their prints are laced up properly.

Posted by Joe Redifer (Member # 3) on 08-25-2010, 06:43 PM:

Sounds like you do as I do, pull the take-up first and then thread through the failsafe and lock it down on the lower constant feed. Christies require a gentle tug, Strongs actually require quite a yank or the platter will fight you for the leader, but never, ever let it drop no matter what platter you use... pull and hold, then thread up.

Posted by Geena Phillips (Member # 3726) on 09-27-2010, 08:54 PM:

On the AW3, check the direction of your film coming back from the projector. If the film twists excessively between the bottom roller and the first cluster roller (particularly if you're feeding onto the bottom platter), it can cause stress marks that look exactly like scratches.

Posted by Sally Ann Burgess (Member # 4746) on 09-28-2010, 01:23 AM:

Hey Geena thanks for that, I don't think it can be that though, we all twist the film the same way (soundtrack faces the tree then faces up on the platter.)
I think Joe Elliot had it right earlier...despite me trying to do the same thing I just couldn't get it to sit off the roller!