failing a knowledgable answer to the above, any anecdotes would help.
stuff like "the leader slipped out of my hands and sure enough, a week later i noticed dirt on the first trailer".

to be clear, i completely advocate keeping the film as clean and dirt-free as possible at all times. i've been trying to train new folks to thread bottom-up (which, in all fairness, is difficult to learn cold), or failing that, to clothes-pin up the leader, which seems to work fine. but since newbies are communally trained (that's one thing i might try to change, if i can), i have to reinforce my spiel with as many facts and arguments as possible so they aren't misled by whatever nonsense someone else might tell them.

I only ever knew of one person that laced bottom up AND IT DROVE ME MAD! His name is Tom Pain, who used to work for the company, he also did most of the install at the Millenium Dome, shame he's no longer about as he's a very good engineer.

I hated it because I insist (at least I try) on consistency between everyone and I couldn't see the need for it. Allowing him to go his own way undermined that consistency... "if he can do things how he likes so can I!".
If I can lace up without film on the floor so can everyone else! Sounds simple, but God is it difficult to get others to do it.

I've thought of electric shock therapy... but is that too drastic? The odd Zap every now and then may not help them learn but it would make me feel much better

I have simulated this before without a projector to test my theory. Here is what happens. You have a brand new film on the platter with X amount of brand new leader. The platter is threaded and during the time when the projector is threaded, part of the leader is dropped onto the floor. Let's guesstimate that this is 15-20 feet into the leader where the floor comes into contact. That 5 foot stretch of leader doesn't go through the projector and your first show is fine. Meanwhile as the film takes up onto the center ring, that 15-20 foot stretch is wrapped around by another stretch say 18-23 feet. Then the next time that dirty stretch from 15-23 feet turns into 15-26 feet, then the next time it goes to 15-29 feet and so forth. By the end of one week's worth of running, the dirt has migrated layer by layer into the first trailer, which now shows dirt.

But that's if the test doesn't include actually running the film through a projector. After the first couple of shows, that leader "that wasn't on the floor" is ran through the projector and the projector does a nice job of spreading it around even more. Splices inparticularly due to their extra thickness do a marvelous job of blowing the dirt in the gate all over the place. This is why on a print that has been playing for awhile you see dirt buildup around the reel change. It works both forward (like my example above) AND backward, which is why you can see on an old print the dirt fire up before the reel change occurs. (This is also why the dirt on the leader works it's way back to the first foot.)

And then although this isn't as bad as letting the film touch the floor, some booths are pretty dusty and having the film threaded down to the 7 second cue point exposes the first part of the first trailer to whatever airborne dust is floating around. This is why automations with start cues are so desperatly needed. My workaround on booths with these kind of automations is to use my standard minimum acceptable length of 75 feet of leader, have the projectionist thread as normal, but when it comes time to start, turn on the motor and only when a predetermined point of the leader hits the projector, press START, then turn off the manual motor. This also puts less stress on the projector as well, but at the expense of losing start timer capacity.

Finally I should point this out, although it is generally the least offender of them all, the platter rollers themselves need to be kept clean as they can transfer dirt particles.

Anyway, if you've got the time to waste you can actually simulate this effect by threading up a platter with brand new leader and a brand new trailer. But instead of threading the projector, stop and let the film just past the projector get thrown on the ground for a minute, then "speed wind" the print (bypassing the projector) deck to deck and repeat. Once you have done this simulated threading a week or two's worth of times, you will see you don't even have to have a projector to collect dirt. All you have to do is let the leader hit the floor.

There is no excuse in the world for not using a clothespin to hold the leader up or threading bottom up. No excuse at all. Every person I've trained to thread bottom up, whether they were a seasoned professional or a newbie has ALWAYS been able to convert within a week to at least or better speed than they did threading top down.

Ken, your tech was right. If you want that kind of consistency in the booth, in your example above everyone else should have been replaced with operators who cared enough to force themselves to learn. Personally though, my definition of "consistency" is not letting the leader touch the floor regardless of how it gets done. If I've got a guy who wants to use a clothespin, or stand on one hand while he threads, so long as the film stays off the floor and the equipment is threaded properly every time, I couldn't care less.

Brad, is this conclusion a result of speculation, or is it a result of measurement? [or somewhere in between?]

I was always under the impression that the dirt around reel changes comes from dirt in film cannisters and other environments that the reels see, before they are plattered. If the displacement of dirt around splices was as significant as you suggest, I would expect to see a similar amount of dirt surrounding mid-reel splices, and I have not made that observation...

My point was he didn't have a reason for doing it.... he just liked to lace up that way. Now if I could reley on everyone to be consistent in that film didn't touch the floor then I'd be happy with it. But the fact is I can't... and to allow everyone to 'go their own way' is in my opinion asking for trouble. That's been proved sooooo many times. Experience is one thing, it should be respected, adopted and adapted. But inexperience, especially if its allowed to 'go its own way' is a real pain in the proverbial!!

Provided you have a reason for doing something a certain way and are prepared to say 'I prefere it that way' rather than its the 'Best and Only' way, then the 'chief' should prevail. He sets the standard and he takes the rap.... I always advise people that provided they do things as they are instructed, then 'if' there is a problem they are covered. Go their own way and they are on their own!! Harsh but fair, as they will seldom accept responsibility for their actions. It is difficult to get the message across as to 'why' something is better this way as opposed to that way....

As for build up around joins, I totally agree. The worst projector for this in my opinion is the Kinoton FP20 upwards series of projector as they have a very long contact path with the film thru the gate. Dust builds up and is then disturbed as a join goes thru. Not only that but the pads are the same covering some 2 1/2 frames of film, more than any other projector. These projectors really do require high standards of operator attention between shows.

This symptom is something I've not seen so much on other projectors, Vic series, Strongs, Westars, Kalee, BTH, Simplex etc etc.
In defence of the Kinoton projectors I should make it clear that gate tension has a lot to do with powdering of print in the gate area. But again it down to explaining and teaching why it's important not to interfere with the correct setting of gate tension etc etc. The one thing you need is time to devote to an individual.... and the one thing you don't have is .......

the problem, as i see it, with this analysis, is that only the base side of the 18-23 feet section will be in contact with the 15-20 feet section that hit the floor. but it is the emulsion side of that 18-23 feet section that then touches the base side of the 21-26 section. so, absent some missing link in the migration process, dirt will only have traveled 3 feet.

the missing link could be that that extra 3' of dirty leader does in fact get threaded through the soundhead and the dirt spreads from there on up the leader. but you observed dirt migration even bypassing the projector, so i guess that leaves the rollers on the platter. even with static electricity, i would hope and assume that dirt transmission requires physical contact. the part of the film path as it leaves the bottom roller of the projector and returns to the platter tree is only a couple inches over the floor and i would hope that dirt isn't constantly making that leap while the film is running.

understand i am not saying what you observed didn't happen, i just feel some of the why's haven't been addressed.

and out of curiosity, how do you bypass the projector when threading the platter? the manual for our christie aw3's says it can be done but doesn't (as i recall) say how. one could thread the wrong way around the top roller on the tree and then back down to the bottom roller, but the film would come obliquely off the roller before the top roller, if that makes any sense.

carl

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Kodak VISION Color Print film is now also very resistant to projector abrasion that caused digital soundtrack degradation and dusting, especially important since few labs still edgewax prints as recommended by SMPTE RP151.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

It's a partial conclusion of both really. Splices (commonly associated with poor film handling practices) AND dirty cans/reels. I'm sure many people here who have screened a brand new print have noticed very minor dirt at the reel changes from the dusty cans and such...and then a couple of months later noticed that the reel joints and lab splices are suddenly dirty. If the film is not cleaned religiously, the print shedding and such will compound the problem. Replacing ultrasonic lab splices with tape splices also seems to aggravate the problem.

Ken,

I haven't had the chance to play with Kinoton's newest line of projectors, but I can definitely vouch that the Cinemecannica V5 is hands down the best projector on the market in terms of being gentle on the print. There is virtually no shedding on these projectors, and even the light bit that there is, it is virtually impossible to scratch the film from it the way it is designed.

Carl,

No dirt migration doesn't require physical contact. I understand your argument and I don't have a scientific explanation as to why the dirt migrates like it does, but it does. This can even be seen on a rewind bench if the film is rewound over and over.

In regards to your second question, click on "tips" and look at the Threading 101 page.

Adam,

I do agree having the projector stop before it tails out is a good idea, however very few automations are capable of doing this. (Insert raving plug for Pennywise CA21 automations here.) What I do is add a minimum of 30 feet of extra tail leader and every few weeks throw it away and replace it. That's overkill since I pass each film through the cleaner on each performance.

John Pytlak's comments can easily be seen with those "Screenvision" advertisements. All dirt within a 10 mile radium will fly through the air to attract itself to those ads. I have no idea what filmstock those ads are on, but for features, Kodak vs. Fuji I haven't noticed any significant difference in regards to shedding and static.