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But what's most important is how the scanner handles film. There are no sprockets -- all the film touches are 3" PTR rollers (8 of them) and the raised edges of the curved teflon-coated gate. Tension can be adjusted so that minimal tension is used on fragile materials, or more tension on VS material that's curly (but the curved gate helps even more).

The prototype machine at the Library of Congress was designed for scanning paper prints, and has restored two Chaplin films (GENTLEMEN OF NERVE and DOUGH AND DYNAMITE), William S. Hart's first film (THE BARGAIN), and has also been used on some nitrate and safety material, including Mary Pickford's lost film LITTLE RED RIDING HOOD, which had, as Frank Wylie put it, the "consistency of a roll of packing tape." It showed last week at AMMI in NY.

When we delivered the prototype machine, someone had donated seven reels of rare WWI footage of the Battle of Liege. It was a nitrate print, in terrible shape. It would break when curved around a sprocket in an optical printer. There was little hope of preserving this film. Since it couldn't take the strain of a sprocket or small roller, the LOC hadn't repaired the perfs (required for printing) because it was likely a lost cause. (And hand repairs of shrunken film take a long time, using an x-acto knife and clear tape.)

So with nothing to lose, we threaded up a roll on the scanner, and hit the button. It scanned without incident, all seven reels. The large diameter PTRs, low tension capability, curved gate, and optical perf sensors all contributed.

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Posted by Jim Bedford (Member # 4) on 07-04-2007, 02:11 PM:
 
John: Love the CAP Code on your pix.
 

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Posted by Steve Guttag (Member # 268) on 07-04-2007, 02:34 PM:
 
Oddly enough...it is the Library of Congress where I am possibly going to be using them. The films will be projected (so they shouldn't be in a brittle state) and the desire to keep any dirt or powdering from the projection from getting on to the film.

I've noted that the standard rollers can be REAL sticky and they make me nervous until couple hundred feet go by. I've read a paper that claims that cleaning in cool water keeps the excessive stickiness down to a minimum and conversely washing in hot water brings out more stickiness.

So John, if you were in charge...which would you use? Matte or Glossy rollers? Do you have a preference for each type?

Steve
 

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Posted by John Pytlak (Member # 331) on 07-04-2007, 07:35 PM:
 
The matte rollers are slightly less sticky, which slightly decreases cleaning efficiency, but they are less likely to have transport "sticktion" and "plucking" of the soft polyurethane by the film.
 

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Posted by Phil Hill (Member # 371) on 07-04-2007, 07:55 PM:
 
Well John, that certainly answers Steve's question with double speak.

(I know you'll kill me for this John since you have so much invested in them, but) Having tons of personal experience with 870 and 1570 applications of the PTRs, I cannot recommend them for anything except possibly for film printers...I've had good luck in that application. The use of them on 1570 projectors is ludicrous!

Dunno know about the application for Nitrate. I only know that the hi-speed of 1570 needs the matt rollers and the slower transports can use the "shinny" ones.

In my experience they ALL have proven to be more trouble than they are worth.

Sorry bub! Just my 2-cents from personal experience over the years.
 

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Posted by Steve Guttag (Member # 268) on 07-04-2007, 08:27 PM:
 
Phil,

Where I use PTR rollers has been VERY effective. That is for archival and EK type prints where the goal is to prevent any cumlative dust/dirt...not for bulk cleaning. I switch them after every reel so there is no significant build up on the roller. One thing I've definately noticed is that the film is CLEANER during the show than during the run through. I normally will use glossy rollers for that first cleaning and matte rollers for subsequent cleanings unless the film was particularly dirty. PTRs only have a limited ability to clean before they fill up and matte rollers has less ability.

Now with Nitrate films...they are by definition archival pieces and irreplacable so my concern is for the film itself. If in doubt, I'm going to use Matte.

Steve
 

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Posted by Phil Hill (Member # 371) on 07-04-2007, 08:48 PM:
 
Well Steve, let us know your outcome.

I personally have not had the same luck as you say you've had.

As I mentioned, the only application I found they were good for is cleaning negatives prior to printing.

(I do have several PTRs here for picking up dust-bunnies and lint from my clothes... they work great for that!)

All the other applications are not worth the time involved to clean and restore them.

Again, just my 2-cents from 15 years of personal experience.

Take it or leave it...
 

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Posted by Steve Guttag (Member # 268) on 07-04-2007, 09:33 PM:
 
I think a difference in my method is that I'm cleaning them after about 2000-feet or less of film...I never let them build up and it is only to keep cumlative dirt off.

Steve
 

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Posted by Gordon McLeod (Member # 33) on 07-05-2007, 10:16 AM:
 
I have always had good luck with PTR on 1570 and found that when we didn't use them the screen dirt was far worse
 

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Posted by Dave Macaulay (Member # 813) on 07-05-2007, 03:15 PM:
 
For 15/70 they won't clean a dirty print, they just don't hold enough dirt and are "full" after the first reel or two. Cumulatively they do clean up a dirty print quite a bit but it takes a lot of passes. With a new clean print - if the booth is kept clean, and it certainly should be - PTRs will pick up the unavoidable dust that gets picked up and they are a LOT better than using nothing.
The vacuum and rotating brush film cleaner used on early Imax projectors is pretty good but doesn't pick up the really fine dust like a PTR does. I've seen film scratches from these cleaners too when something abrasive gets stuck in a brush, a chunk of grit small enough to stick on the PTR might cause damage but I haven't seen it.
 

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Posted by Paul Mayer (Member # 355) on 07-05-2007, 03:59 PM:
 
We had great luck with the PTRs at the Caesars Omnimax once we started using them. On a newly-received built-up print (usually covered with wood chips and shipping dirt even if it was wrapped with garbage bags) yes the rollers loaded up very fast. So on these new (to us) prints we had the field flattener cycle every few seconds for the first several shows. That, combined with changing and cleaning the PTRs every show, and changing out the field flattener wiper bars too, had the print cleaned up after a few passes.

Once the print was cleaned up, we'd put the field flattener back to its normal setting (about 20 seconds IIRC) and the PTRs kept the print looking good. We had two sets of rollers, which were changed for every show. The off-show set was cleaned by hand rubbing them under running water then blown dry to be ready for the next show. Visually inspecting the rollers during cleaning let us know how we were doing in regards to keeping the booth clean as well.
 

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Posted by John Hawkinson (Member # 1135) on 07-05-2007, 04:34 PM:
 
One thing I recall seeing are photos of lab equipment with multiple pairs of PTRs in series, rather than just a single pair. I could see that working a lot better.

We have PTRs in our principle 35mm changeover house, and we do find them effective (Sometimes we FilmGuard on the inspection bench if things are really bad, though). We also wash PTRs at the end of each night, which for us is two shows. If print is really dirty, we'll wash PTRs faster. Cleaning them every reel makes a dramatic difference on prints that are abysmally dirty.

--jhawk
 

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Posted by Mark Gulbrandsen (Member # 72) on 07-05-2007, 06:06 PM:
 

quote: Paul Mayer

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We had great luck with the PTRs at the Caesars Omnimax once we started using them.

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Paul,

I'm not really sure how you would have been able to tell one way or the other as the screen there was so abysmaly filthy for about the last 5 years that place operated!!

Mark
 

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Posted by Paul Mayer (Member # 355) on 07-06-2007, 02:01 AM:
 
Easy. The print dirt moved or flashed by. The screen dirt didn't.
 

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Posted by Leo Enticknap (Member # 534) on 07-06-2007, 06:50 AM:
 

quote: John Pytlak

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The Library of Congress uses film transfer devices built by Jeff Kreines, which uses PTR rollers for both cleaning and transport.

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More on the Kinetta datacine can be found here (PDF).

I've used an RTI manual film cleaner with PTRs on nitrate elements, winding slowly and stopping as often as is necessary to remove and clean them. If there's a lot of ingrained dirt in there, this can sometimes mean stopping every 200-300 feet or so. As a purely subjective observation, I found that as nitrate is so much thicker than acetate or poly and the base side is a bit more tactile, the PTRs really did lift out a lot of crud.

The only problem I can foresee using them in a projector is where in the film path you're going to put them without creating a fire risk. If the spool magazines and mechanism are all enclosed with a fire trap between them, then the PTRs are going to have to be mounted somewhere within the enclosed film path, and on most of the projectors I've worked with, I can't think where. There might just be space in a DP-70 if you removed the mag head assembly, I guess, but that's all I can think of.
 

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Posted by Scott Norwood (Member # 30) on 07-06-2007, 07:50 AM:
 
I've not had much luck with PTR rollers and prints that are already dirty. They do collect quite a bit of dirt, but the image on screen never looks any better.

I do think that they are useful when starting with a new (or very clean) print and the rollers are used and changed (or cleaned) for every show. Under those conditions, prints seem to stay cleaner than if no cleaning method were used.
 

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Posted by Steve Guttag (Member # 268) on 07-06-2007, 08:22 AM:
 
In this instance, I was not going to use them on the projector BUT it really depends on the fire laws that govern the specific facility. Some require nothing more than fire rollers and magazine. if you think about it, the fire, if started won't be in the mechanism very long even if it starts there. It will quickly try to spread to the magazines and either the fire rollers succeed or they fail and the fire will then be in the soon-to-be-melting magazine.

If you are only required to have magazines/fire rollers for Nitrate compliance, then projectors like those from Kinoton can have PTR rollers incorporated into the film path just like a DTS reader. I believe that Kinoton has a version of their SP75 that has a full door/magazine with PTR rollers in the film path for special venue applications (the door is probably for noise and dirt reasons for they don't normally offer doors anymore).

Steve
 

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Posted by Mark Gulbrandsen (Member # 72) on 07-06-2007, 10:13 AM:
 
I've seen a number of prints that seem to give off and flake a white powder, this is even noted during the make up of these brand new prints before they are even run. This screws the Sony 3000 systems big time and they can't read the digital tracks worth a hoot. But repeated cleanings with the PTR's has saved these prints and the Sony's play fine after about a half dozen cleanings. Anyone else see this stuff comming off prints?

Thanks
Mark
 

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Posted by Brad Miller (Member # 2) on 07-06-2007, 12:28 PM:
 
Oh Steve, you and your reel to reel fetish.

Just load up the film on a platter! Put the platter in another room (both booth and platter room being fire-rated). Run the film through a tiny sealed opening in the wall with fire rollers (or use two sets of fire rollers if you like) and also rig up "film chopper" failsafes on the feed and takeup lines.

I know it may sound dumb, but in reality I could see this as being much safer.
 

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Posted by Mark Gulbrandsen (Member # 72) on 07-06-2007, 01:59 PM:
 
WOW! The thought of 12 to 15 thousand feet of film going poof all at once! I bet it would even melt the alumnium platter decks! Neato!

Mark
 

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Posted by Steve Guttag (Member # 268) on 07-06-2007, 02:16 PM:
 
Actually, you are allowed up to 75 lbs of Nitrate in the projection room at any one time so the potential for 12-15K feet catching fire at once is already there. The key to the law is that you are not allowed to "shield" the film from any sprinkler. It isn't about trying to put out the fire once it has started (you can't do that) but trying to keep the remaining film from catching fire. A Nitrate rated film cabinet is one that actually has the sprinkler head INSIDE the cabinet.

Actually what Brad stated is true...having the "reel units" at a distance would give a much greater chance at being able to cut the film BEFORE it reaches the pack. You would just need really long leaders and tails for each reel

Steve
 

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Posted by Brad Miller (Member # 2) on 07-06-2007, 03:09 PM:
 
Which is why a tower or even just a rig for 2000 foot magazines OFF of the projector would work good too...it's just that I get such enjoyment out of using the "p" word around Steve.
 

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Posted by Leo Enticknap (Member # 534) on 07-06-2007, 03:56 PM:
 
I can kind of see Brad's point. If you could design a system that is, at the very least, 99.999999% guaranteed to cut the film and stop the fire spreading to the platter room, then you have a scenario whereby a fire only loses you, say, 20-30 feet rather than 2,000. I've seen footage of fire cutters in spoolboxes activating, and they do work. The downside, of course, is that if the fire does get to the film pack on the platter ... well ... anyone who has the misfortune to be in the platter room at the time is going to win themselves a gold plated Darwin award. And, of course, you've lost the whole print (not to mention your theatre, your customers and half the neighbourhood, but wearing my archivist's hat, I'd be more worried about the print ).
 

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Posted by Brad Miller (Member # 2) on 07-06-2007, 04:17 PM:
 
Leo,

How about this then? One projection booth with 2 projectors. Two smaller rooms with a feed and takeup fire rated magazine with fire rollers and choppers. In the walls are fire rollers and choppers for the film to pass through to get into and out of the booth. You run on 2000' (or even 1000') reels. The rest of the print is stored in another room entirely. Two projectionists, one to standby the machines, one to thread up the next reel.

Furthermore you add a new motor start cue with grease pencil (or an automation cue) noticeably ahead of the standard motor start cue such that you are able to use an extended length mylar leader. That way if reel 3 should catch on fire and anything happen, there is only mylar leader from reel 4 flying across the projection room.
 

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Posted by Steve Guttag (Member # 268) on 07-06-2007, 06:07 PM:
 
Actually, the 2-projectionist thing was a given...in fact it is normally three. One at each machine and one to hand the next reel or remove the projected reel. You are not to leave nitrate film unattended...even if sitting idle in the non-used projector. Remember, the gate/trap may still be warm/hot from the previous reel. The idle machine could still be the source of a fire and the projectionist is the first line of defense to stop it early or get everyone out as quickly as possible with minimal damage to people and property.

I had presumed Brad's scenerio was still 2-projector with the reels just spinning at a distance from the projectors in order to have sufficient time for a chopper to prevent the fire from spreading. There is definately merit to the idea.

I guess a loop cabinet or Brad's delayed interlock is out
 

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Posted by Stephen Furley (Member # 1277) on 07-07-2007, 02:49 AM:
 

quote: Steve Guttag

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Actually, you are allowed up to 75 lbs of Nitrate in the projection room at any one time so the potential for 12-15K feet catching fire at once is already there.

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quote: Stephen Furley

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Leo, do you know who now owns the rights to 'This film is Dangerous'? I wonder if they would allow a download of it to be made available on this site.

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It was commissioned by the Royal Navy (BFI database entry), so it'll be Crown copyright. The rights to Crown copyright film material are now administered by Film Images, who typically charge full commercial rates for this sort of thing. That having been said, I'm sure they'd be very unlikely to take action if the film sort of accidentally-on-purpose found its way onto YouTube (lots of other government stuff is on there and has been for ages)... wish I had a copy.
 

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Posted by Tim Reed (Member # 137) on 07-07-2007, 09:19 PM:
 
Thanks, Leo. I might just head up there for that, as I service the Dryden Theatre.
 

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Posted by Leo Enticknap (Member # 534) on 07-08-2007, 11:30 AM:
 
Great! I've just been speaking to a friend who is on the conference committee, who tells me that the programme on the website already has a few bugs in it, and probably won't be updated with a final version before the end of the month. There's no final decision yet as to what the nitrate screening will be, but apparently an almost pristine print of Crossfire from the GEH collection is in the frame (or should that be on the platter? ). If I hear anything definite before the website's been updated, I'll make sure to post it here, and hope to see you in September.
 

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