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Topic: Tick Marks

Brad Miller
Administrator

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

posted 09-02-1999 11:30 PM

That's why. Old acetate stock, old lenses. Everything there is very outdated by today's standards. But for the time, SMPTE's recommendation was probably a good one. Just not today.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 09-08-1999 03:44 PM

Sorry for the lag time in the reply, here. I'm a technological 'have-not'...

I've pretty much eliminated the platter from the list of suspects. I just sat there on a stool and watched the film run for a while and even though I have the old, non-removable brains on my Speco platters, they are pretty much okay.

I'm back to investigating the rollers. I think it's a pad roller, but I'm not 100% sure.

The damage is on the extreme right side of the picture. Only a few inches to the inside of the masking. In fact, the 'keystone' effect cuts it off at the bottom of the screen. It appears as little white dots. At first glance, I thought it was DTS code but then I thought, "HEY! DTS is on the OTHER side of the screen!" At first, there are only 3 or 4 ticks. Then, over time, it builds up until there are about 50 of them. They DO appear to travel up the screen. Looking at the film under the light reveals that there is a thin strip of abrasion down the inboard/non-soundtrack side of the film, just inside the sprocket holes on the emulsion side. It is only 1/16 inch wide. maybe less.

Brad, I'm going to the theatre and getting a clip of the film to send. -- Thanks!

My theory is that there is a small, almost microscopic pit on one of the rollers. I might put some "High Spot Ink" on the rollers one at a time and run a film loop (Old film). The ink will rub off the rollers and make any burrs or pits in the rollers turn blue. What do you guys think?

What's "high-spot ink"??? -- That's what they use in machine shops to tell if the parts that they are making are perfectly flat. It's a blue 'paste' that you spread on a straight-edge and rub on the part that you want to check. The ink transfers to the part and the pattern of the ink tells you where you have to have to remove some more of the metal. (Of course I'll be careful not to get the stuff on any parts of the proj. that I'm not specifically looking at AND I'll use old film that I don't care about.)

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Brad Miller
Administrator

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

posted 09-08-1999 03:57 PM

Have you checked your pad rollers? Some of the older projectors had a little ring just inside the sprocket area instead of like the newer rollers do which only have the outer flanges to them. That would make tiny marks on the absolute extreme edge of your picture (and right analog sound track).

Perform this quick test...

Grab yourself a trailer and cut yourself 3 strips of film 6-8 inches long.

Now insert 2 strips into a pad roller/sprocket and close the pad roller assembly. Does the pad roller spin freely? It should.

Now insert 3 strips and check to see if the pad roller will spin freely. It should have a bit of a drag to it.

If your pad rollers are a touch too close to the sprockets, there's your problem. It will also explain why it takes so long for the tick marks to appear.

Note: make sure to use normal film stocks from a recent trailer and not a test loop or other film stock.

As to the strip of film, just cut off a foot of it and stick it in a regular envelope. You can mail it to:
Film-Tech
9794 Forest Lane PMB356
Dallas, Tx 75243-5702

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 09-08-1999 04:14 PM

Thanks, Brad.

I just got off the phone with the theatre. I'm having them clip a few frames out of the 'blue band' at the end of the print. It will be in the mail as soon as I get hold of it.

Yes, the pad rollers have that little 'ring' on them. I'll be checking them too.

Today is my day off. Not working again till Friday. I'll be checking the pad rollers the moment I get to work.

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Brad Miller
Administrator

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

posted 09-12-1999 01:52 AM

Received your letter with the sample piece of film. Your problem is definitely the holdback sprocket's pad roller in the soundhead. It is too tight up against the sprocket and causing abrasion. Your other pad rollers in the projector head are fine.

Might I recommend to first get yourself a small allen wrench to remove the cap from the end of the pad roller shaft. Then remove the roller itself. Closely under a light, inspect for any abrasion on the inboard "ring" of the pad roller. Somewhere on there is a tiny, tiny nick. You might be able to smooth it out with some fine grain sandpaper, but your problem will go away if you simply adjust the machine screw stop on the arm of the pad roller so that there is more clearance between the pad roller and sprocket. The ideal way to do this is 2 messages above. Remember, the pad rollers should NOT turn with film running, but be able to spin freely without so much clearance that the film can jump the sprocket. Ideally of course, you should replace the pad roller too.

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Gordon McLeod
Film God

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

posted 09-13-1999 11:48 AM

There use to be problems with a padroller used by century and simplex that didn't have a inner flange on the inboard side of the sprocket holes. Rick Long will probably better remeber for I think it was at the fairview in toronto that a similar problem was cured by changeing the pad rollers

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 09-14-1999 05:33 PM

I have checked the roller like you said. It was the holdback's pad roller. There was a little nick in it too. You really had to squint to see it but it was there, none-the-less.

Went to adjust the roller and found that the shaft on that roller was bent! I guess that's why only one side of it was hitting.
If you chuck the shaft in a screw gun and spin it, you can see it wobble as it spins.
A new shaft and pad roller are on order. I've adjusted the roller as best as can be expected. (Twisting the bent shaft in its mounting hole before you tighten the set screw helped me find the best fit with the least possible damage.

It's been running since last Saturday with a new print and no damage yet.

Your help is much appreciated, Brad. I've been telling people about this site at work.
People here at TT17 are much impressed.
Thanks again.

Randy

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Art Averett
Film Handler

Posts: 14
From: Orlando, FL
Registered: Mar 2000

posted 09-15-1999 03:55 PM

Randy has the right reply. Order pad rollers from Lavezzie. The phone # is 1-800-323-1772 or fax them at 630-582-1238.

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