Film-Tech Forum ARCHIVE: Prints shedding on Simplex

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Posted by Andy Uhrich (Member # 3169) on 07-12-2005, 11:33 AM:

Hi,

We have a couple of Simplexes and black and white prints shed horribly causing the picture to go out of focus, often to the point that it can't be put back in focus. Once the shedding was so bad that the print got stuck in the gate and the frame burned. Does anyone have an idea of what is causing this and what can be done to stop it.

Thanks for you help,

Andy

Posted by Randy Stankey (Member # 64) on 07-13-2005, 11:08 PM:

The exact model number (PR-xxxx) will help us help you a lot better.

Check your gate area first.

Make sure there aren't any burrs or nicks or anything like that which will scrape the film. Look on the gate runners, the tension bands and any "film-bearing surfaces". Make the same check on the intermittent sprocket pad shoes. Then make a similar check on all your sprockets, pad rollers and anything else that the film touches.

If you have checked all of that and you STILL haven't found the cause you're probably going to have to call your technician and have him check your gate tension and alignment.

Throughout all of this, we are, of course, assuming that the film is always threaed correctly and isn't touching anything it's not supposed to.

Here's the kicker: Once the film is "scuffed" it will continue to shed even AFTER the problem that caused it has been solved. It my get better after a while but it will never go away completely. If you put another print through that projector without solving the problem first you will damage another print FOREVER.

Your best plan of attack is to take a vacuum cleaner hose and a paint brush and give that projector a super-duper cleaning. Then take some old trailers and splice them up into one long "mini-movie". Run them through about a half dozen times. Then look inside the projector to see where the most dirt is. With a litte luck the pile of dirt inside the projector just might lead you to where the problem is. If not, you can use that film as a "telltale" to see where the damage is coming from. More on that later... if we even get that far.

Go check for a damaged gate, etc., first. [Smile]

Posted by Monte L Fullmer (Member # 2797) on 07-13-2005, 11:22 PM:

True, Randy's asking what kind of "PR" machine you have (a PR-1014,1050,1060..etc..), or do you have an old black case "XL" machine?

I had the similar experience with PR-1050's with one machine had the trap and gate (flat gate and trap style) that the gate was closing too tight and causing shedding.

If's a 1014 or later, there is a stop allen screw located on the inboard side of the trap that "stops" the gate at a certain point when closing the gate. This allen screw will turn in to cause the gate to close too tight and will shed film like mad.

If's it the flat gate style, the runners and guides on the trap could be worn, wear spots and grooved to cause this problem.

-Monte

Posted by Steve Guttag (Member # 268) on 07-14-2005, 05:41 AM:

Pssst. Monte...even "XL"s had "PR" numbers. The first PR-1014s was a black wrinkle finish. The "PR" number will let us know exactly what machine you have and if further questions need to be asked.

Posted by John Walsh (Member # 168) on 07-14-2005, 07:08 AM:

Is it with B&W prints only? I've run several B&W prints that shed. It would also happen with IB prints. There was a hard, dark-white colored build up on the gate bands. The build up could be little on one side of the gate, while a lot on the other side, resulting in the image out of focus on just one side. A through cleaning after every show was the only thing I found that reduced the problem, but even then it was pretty bad after 8 weeks.

Posted by Brad Miller (Member # 2) on 07-14-2005, 10:45 AM:

Black and white filmstocks tend to shed in pretty much every projector, even one which is not scuffing the print in any way. I'm sure there will be people who will argue the point that if everything was absolutely perfect with the projector that this wouldn't happen, but in most cases you will drive yourself insane trying to track down the cause if you don't also experience that kind of shedding on color prints.

Just get yourself a bottle of FilmGuard. It will stop the shedding.

Posted by John Pytlak (Member # 331) on 07-14-2005, 03:34 PM:

Kodak has recommended proper lubrication of prints after processing since the 1920's, to reduce projector abrasion of the film. The recommendation is in Kodak's processing manuals, and in SMPTE Recommended Practice RP151. Unfortunately, restrictions on the use of solvents to edgewax film have caused most laboratories to not lubricate prints (e.g., methyl chloroform / 1,1,1-trichloroethane depletes the ozone layer).

Kodak does put lubricants into the film formulation, but there is a limit to how much can be added without making raw stock rolls too slippery.