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Author Topic: PTR Rollers and Nitrate film Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 07-06-2007 06:50 AM                        quote: John Pytlak The Library of Congress uses film transfer devices built by Jeff Kreines, which uses PTR rollers for both cleaning and transport. 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.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 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.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 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  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 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  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 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.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 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  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 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  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 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.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 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 ).  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 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.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 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  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 07-07-2007 02:49 AM                     quote: Steve Guttag 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. I suspect that the regulations varied considerably from time to time, and from place to place. The ones that I read, from the '50s I think, required spoolboxes to be constructed so as to contain no more than 2050 feet of film, and no film was allowed in the projection room other than one reel on each projector, i.e. the previous reel had to be removed to the rewind room before the next reel was brought in. Interesting that your limit is for weight of film, rather than length. Of course, that would halve the length, and more than halve the running time, with 70mm nitrate film. I'm not sure what the regulations were here for 70mm film, or indeed if Fox Grandeur was ever actually shown here. I can see the logic behind Brad's design, but of course, nothing like it exists, so you'd have to build it new, and I think the chances of that are just about nil. I think you'd actually find it very difficult to get a nitrate licence for any projection room not already licenced, at least in this country, whatever precautions you built into it. I suspect that the licencing authority would simply throw their hands up in horror because nitrate film is so 'dangerous', and almost every other cinema manages to get by without having to use it, and it's something that they're simply not familiar with. Probably easier to get a licence for a LPG cylinder depot, like the one at Bow, in East London, which has housing and shops close to it, and a very busy road running right past. I'd be rather more concerned about living next door to that than to a properly equipped cinema which occasionally runs the odd nitrate print. The person who has to actually make the final decision has probably never even seen any nitrate film, and is probably going to be concerned about their legal responsibility/liability if they had approved the application, and there was a serious accident. I think it would be even more difficult to get them to accept a completely new design, unlike anything that had been done before, e.g. Brad's design. I'm not certain, but I think that NFT2 in London may well be the last new public cinema here to be granted a licence for nitrate; I think it opened in about 1970. In a recent edition of the BKSTS magazine 'Cinema Technology' there are some pictures of the nitrate installation in one of the NFT projection rooms, I think it is NFT1, but I don't have it with me to check. Things have changed somewhat since I was last up there, about eight years ago. 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.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-07-2007 06:15 AM                     Nitrate in the States is governed by all authorities. That is, one must satisfy Federal, State, local authorities...not just one. But, if you think about it...there are not too many theatres that would WANT to run it...the hoops you have to go through to have an approved facility. However, you also have to deal with transporting it too. As such, it is mostly archives themselves with their own nitrate storage are the ones that have people on-hand all the time that know what it is and how to handle it that are still dealing with it today. Archives have a mix of perserving the films (not wanting them handled any more than necessary) and wanting to ensure others can enjoy the things from the past. As such, Nitrate showings are a rare treat available only in a few theatres in the Country. As to the 75-lbs rule...that is from NFPA-40 which is the Federal code governing Nitrate facilities and the 75-lbs rule only applies to the projection room. Since that is a fire code, I'm sure the goal to regulate how much "fuel" can be in one place at one time. What I found strange was that the code isn't really concerned about having the film covered while in the projection booth. Instead it was concerned about NOT having it up in such a manner that it was shielded from the sprinkler system. Note, a sprinkler head is to be above each magazine.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 07-07-2007 07:15 AM                        A quick plug, while I remember: for anyone who can make it to Rochester, NY, in the last week of September, we are planning to show some nitrate material from the GEH collection at this year's AMIA conference. The provisional screening date is Wednesday 26 September from 7.30-9pm. The exact programme details haven't been finalised yet, but this will be the first time we've been hosted by a venue which can run nitrate (the Dryden Theater), and as Steve says, it'll be a rare treat. We've always opened our evening screenings to the public as well as conference delegates, and can't think of any reason why it won't be the same this year. I'll post more details as soon as I have them. Some of the larger archives are in fact sitting on quite substantial collections of nitrate viewing copies. The usual scenario is when a print has been acquired and a safety dupe neg (or, if necessary, separate pic and track negs) made for preservation, but the budget wasn't there for a safety viewing print as well. In these scenarios the nitrate print is available for access, because it's no longer the main preservation master; but usually it'll only be used for telecine. The last I knew, the BFI had around 1,500 feature film titles that exist as nitrate viewing prints. Brad's system sounds good, but to be honest, I'm not sure if it isn't a little bit of overkill. The spoolboxes with tapered lips facing away from the operator are designed to allow a reel of up to 2k feet to burn itself out without damaging anything within a specified vicinity. Assuming that all works, the main danger is from the toxic nitric acid fumes that the fire generates. As long as fire shutters on the porthole work and the projectionist(s) evacuate the booth immediately, the spool magazine should contain the fire. quote: Stephen Furley 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. 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.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 07-07-2007 09:19 PM                       Thanks, Leo. I might just head up there for that, as I service the Dryden Theatre.  |  IP: Logged

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