IMHO, compressed air should NOT be used. Indeed, you are just stirring up the dirt. High pressure air jets can be especially bad around lenses, where dirt, moisture and oil can be forced into the optics. Use a vacuum and brush to pick up any loose debris inside the mechanism (make a fitting so you can have a tiny vacuum hose for tight spots). Wipe up any oil with an absorbent cloth.

Damp film is funky, sticky, and requires a lot of TLC to baby until it is dry. By a damp rag, I mean a lint-free rag spritzed once with a spray bottle of (ditilled) water and massaged, just to give the rag some "tack." This will not wet or even dampen the edge of the film as you brush up the dust. It also will not redistribute or remove the edge wax, which could happen when using some solvents. Using Film-guard could be an option, though. I leave that one to Brad's expertise.

I suppose one could vacuum a film on a platter, though I've never seen it done as far as I can recall. Could that cause static problems? Air moving at velocity can be a way of moving electical charges.

I'd be curious to learn the results of tests of the various methods. I suspect the _lightly_ dampened rag might win out in removing dust.

Re: starting cars and gunning them. I can think of many many shade tree mechanics that do this. When I lived in apartments, I used to take perverse delight in walking up to these fellows intent on tuning engines and waking me up at 9AM on Sunday morning after I'd just arrived home from the midnight shows, and casually saying "Ya know... you could throw a rod doing that." It usually wasn't appreciated, but it was fun anyway.

1) Any dust in the projector is instantly accelerated to the speed of sound. No matter how inoccuous dust may seem when it's standing still, it would be like a sandblaster when it's moving at that speed. Continued use of a comressor without removing the bulk of the dust, IMHO is just asking for trouble.

2) I have seen projectors that have been cleaned exclusively with compressors. The visible areas like the trap look squeaky clean. But when you remove the trap you'll find all kinds of dust bunnies caked around the inner workings. Same goes for the sprocket bearings. I have taken sprockets off and found a ring of icky-goo caked around the shaft. This is rarely the case with projectors that are cleaned exclusively by hand.

3) When you compress air you are also compressing the water vapor in the air. Take the nozzle and put it up against a smooth surface or a piece of glass or something. You'll see little droplets of water forming as it is blown out at high speed. You might as well clean the projector with a garden hose!

4) If you use a compressor that has oil in it and don't use a oil/vapor trap you'll get water vapor AND oil vapor. That's even worse.

5) How many people do you think would really be careful and not knock the nozzle around inside the projector?

6) Why the heck do you want to lug the compressor around with you? You can do a good job of cleaning the thing with a shop rag AND it'll take you a fraction of the time.

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I agree that film puts a negligible load on the projector drive train (you measured no acceleration difference with your tachometer), but the load on the intermittent components is significantly higher with film in the gate. The gate often provides quite a bit of back-tension on the pulldown sprocket, especially when the film has been sitting in the gate overnight (core-set and "stiction" of the emulsion). Even a few ounces of film tension puts quite a strain on that relatively tiny starwheel slot and cam pin at the high accelerations required. Running the projector a few minutes without film to "warm it up" and distribute the oil is good practice.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

You know how powerful the air compressor can be, well imagine if the air compressor sucked air into the nozzle instead of out. Imagine all the loose film debris and gunk you could clear up - but be careful you don't suck the oil straight out of the machine

Has anyone thought about a platter cover that can cover the film when it is playing?

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One of the things about PTR film cleaning is that it is very easy to analyze the dirt that is being removed from the film.

Under a microscope, it is easy to tell whether the debris is film-related like base or emulsion, or from other sources like construction debris, bearing wear, packing materials, carpeting, linty clothing, or even dandruff. The most "unusual" debris captured on a PTR that Kodak analyzed was identified as "hemp". Wonder where THAT came from???

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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