quote:

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Also the same concern for Q-tips(tm): don't clean the optical sound without doing a Dolby alignment

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umm...why? Assuming your last A-chain was done with clean optics, then all mechanical and electronic failures aside, dirty optics will always stand in the way of good reproduction...
 

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Posted by Mike Olpin (Member # 1115) on 02-08-2004, 03:17 PM:
 
Lenses are cleaned once a week. All projectionists are trained how to do this properly.

Same goes for the soundhead. Since we started regularly cleaning them, the analog sound quality has improved.
 

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Posted by Scott Norwood (Member # 30) on 02-08-2004, 03:47 PM:
 
Why is the booth so dirty that your lenses need to be cleaned weekly?

No need to use the lens cleaner and lens paper that often. It should be sufficient to blow the dust off with a blower brush (available at camera stores; do _not_ use compressed air!). For the most part, the lens paper and lens cleaner fluid should be saved for cleaning off fingerprints and such, especially if you have newer (1960s and later) lenses which are coated (the coating can be removed with excessive cleaning).

In a multiplex, I vote for having a shop rag and toothbrush next to every machine. A central compressed air system (or, better yet, vacuum) is nice to have, too. Sprockets, gates, and traps should be cleaned between every show (with exceptions for theatres using FG).
 

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Posted by Mark Gulbrandsen (Member # 72) on 02-08-2004, 04:17 PM:
 
"The best thing you can do with a lens is to never touch it except blowing dust off of it."
_________________________________________________________________

Ouch! Thats a Bozo no-no!

Of course this is the equivelent of sandblasting a lens(literally). When I did lens repair at Canon USA we were taught to never blow off a lens with air. Large debris was removed first with a camels hair brush and then we used Kimwipes lightly wound around and slightly overhanging the end of a large tweezers. This was dipped into a solution of 40% MEk and 60 percent denatured alcohol. This is done in a circular motion starting from the center and working out and does require some practice to do it right. I still do it this way today and a lens can end up looking like new and is spotless and void of any dust for at lesat a while. If you ahev alot of elements to clean the MEK gives you a great high as a side bonus . Ah yes the gold ole days at Canon when they made fine lenses and cameras....but no longer.

Mark @ CLACO
 

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Posted by Chris Medley (Member # 2145) on 02-09-2004, 01:57 PM:
 
Mark,

Is there a reason for the MEK/Alch. Mix?
 

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Posted by Mark Gulbrandsen (Member # 72) on 02-10-2004, 09:23 AM:
 
Chris,
I believe the MEK helped it all to evaporate at an even rate...quite rapidly actually...also so there were no water droplets left behind fomr the alcohol. I never asked them about their proprietary mixture but if one just uses alcohol it leaves somewhat of a mess on the glass.

Mark
 

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Posted by Chris Medley (Member # 2145) on 02-10-2004, 11:03 AM:
 
thanks for all your input
 

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Posted by John Pytlak (Member # 331) on 02-10-2004, 09:07 PM:
 
Lens Cleaning:

http://www.schneideroptics.com/info/white_papers/lens_cleaning.pdf

Be careful when using MEK -- it will dissolve some materials, especially plastics and adhesives. Likewise acetone.
 

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Posted by William Hooper (Member # 71) on 02-11-2004, 12:12 AM:
 

quote:

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Be careful when using MEK

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It's also regulated as a carcinogen, & as having an inhalation toxicity of HIGH.
 

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Posted by John Pytlak (Member # 331) on 02-11-2004, 06:47 AM:
 
MSDS for Methyl Ethyl Ketone (MEK):

http://www.astrochemicals.com/10080.pdf

http://www.2spi.com/catalog/msds/msds02850.html
 

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Posted by Pete Lawrence (Member # 130) on 02-11-2004, 11:26 AM:
 
The MSDS links that John provided completely contradict each other when it comes to first aid for swallowing MEK. I wonder what else they messed up on?

Anyway, unless your state has banned it, MEK is available in the paint department at your local Home Depot.

It's a great solvent, but it sure stinks.
 

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Posted by John Pytlak (Member # 331) on 02-11-2004, 04:05 PM:
 
Remember, it is the responsibility of the vendor of the material to supply the MSDS, based on the data and testing they have done. So it is possible that different vendors may have different MSDS information, although the data will usually be consistent. (That's why I posted links to two different ones).
 

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Posted by Ken McFall (Member # 845) on 02-11-2004, 04:13 PM:
 
I have to agree that it's not a good idea to have every possible cleaning solution at each projector. I've removed everything except a yellow duster, Jack Roe sprocket brush and a small 1" paint brush from ecah projector. I've also taken to stopping the use of the compressed air gun to 'Clean' the projectors after each run!

Compressed air was only ever to be a tool, to assist in cleaning and never to replace cleaning of the projector.

I've supplied my own Driklen cleaner and have started to FilmGuard every print.... the difference is astonishing!

There is now NO build up on the gate plate or runners and no dust from the print at all. The only change to normal operation is to increase the gate tension for the first couple of runs.

Using air guns only spreads the dirt all over the mech, sound optics and lenes!

I agree that lenses should only be cleaned when needed so the risk of scratching is reduced. The same goes for the sound optics.... The only way they are going to get dirty is if dirt is sprayed onto them! So don't use air and they stay cleaner for much longer.

Film Guard plays a very improtant part in keeping the film itself and the projectors clean. So reduce the dust etc from the prints and you reduce the number of problems that inexperienced hands can inflict on the show while attempting to clean equipment.

As for using solvents on the equipment.... never! I've never found solvents any good at removing build up on gate plates anyway.

I like the idea of having a trolly with all of the special cleaning solutions required. It could also house all of the specific tools needed to work on the equipment when carrying out maintenance etc.
 

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Posted by Steve Kraus (Member # 476) on 02-11-2004, 10:42 PM:
 
I wasn't suggesting blasting lenses with high pressure to clean off abrasive grit but if it's just ordinary lint-like fibers out of the air then I think blowing it off with one's breath or very gentle gas (at a sideways angle) is preferrable to anything involving direct contact.
 

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Posted by Mark Gulbrandsen (Member # 72) on 02-11-2004, 11:11 PM:
 
Clearing the surface of a coated piece of glass with a camels hair brush has been the norm since the dawn of photography. Somthing to do with the softness of camels hair. While ones breath might not hurt the coating the chance of slobbering on the glass when one blows on it is also there. As for bottled gas I really dislike the stuff and if the bottle is aimed at an off angle the bottle can also emit a bad residue thats very difficult to remove. Perhaps John P. can elaborate on whats in those cans of compressed gas you buy at the store. I use them myself but mainly for cleaning the dust out of my computer and keyboard.

Mark @ CLACO
 

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Posted by Erika McCarty (Member # 2006) on 02-11-2004, 11:20 PM:
 
Well, Chris, I would agree only the basics (brush, rag, toothbrush) are neccessary next to all 14 projectors.

Our booth isn't THAT big...a little walking never killed anyone.
 

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Posted by William Hooper (Member # 71) on 02-11-2004, 11:50 PM:
 
Well, there's a memory slip. I remember it being regulated as a carcinogen by OSHA back in the 80s or so.
 

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Posted by Chris Medley (Member # 2145) on 02-12-2004, 01:10 AM:
 
Thanks Erika...you know I always like your input....well...most of the time...kidding
 

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