This is topic Denatured alcohol to clean port glass in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by John Robert Jones II (Member # 5404) on 09-02-2009, 05:59 PM:
 
Hello,

I work at a theatre where I've been told by several technicians over the years to use denatured alcohol with a chamois to clean port glass windows. However, our newest tech has now told me not to use that solution any more. Any one know what I should do? I find it hard to believe that other techs have been wrong all along.

Thanks!
 

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Posted by Jeremy Weigel (Member # 4208) on 09-02-2009, 06:23 PM:
 
I think this is more of a preference by your current tech; not that your other techs were "wrong". I could see not using it because of its higher flammability compared to lens cleaner. We use lens cleaner only for the area where the image passes through the glass so that we have a virtually streak-free and haze-free result when used with Kimtech Kim-wipes or Science Precision Wipes (prefer these since they are a larger sheet; 11.8"x11.8")
 

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Posted by Mike Blakesley (Member # 26) on 09-02-2009, 07:10 PM:
 
I always thought that the thing you use to wipe it with is more important than the cleaner. As long as you use a soft cloth like terry cloth, any good glass cleaner will work (at least, so I've been told!)
 

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Posted by Robert E. Allen (Member # 1351) on 09-02-2009, 08:21 PM:
 
I use the alcohol and a lint free wiping cloth as it leaves no haze on the glass. Don't know why your tech would say that. Just about everything else does leave a haze.
 

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Posted by Sally Ann Burgess (Member # 4746) on 09-02-2009, 10:28 PM:
 
White vinegar and newspaper. I wipe using horizontal strokes on one side, and vertical on the other. That way, if there are any streaks I know what side they're on.
No streaks so far.
 

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Posted by Jack Theakston (Member # 4484) on 09-03-2009, 01:59 AM:
 
Windex and newspapers work wonders for me as well, but I'm sure there's someone out there that will scoff at that.

If you want to get REALLY anal about dust, you use astronomers use to clean lenses-- non-flexible collodion, a volatile liquid which creates a "skin" that you peel back after it dries.
 

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Posted by Monte L Fullmer (Member # 2797) on 09-03-2009, 02:47 AM:
 
I've done Isoprop Alcohol in a spray bottle to clean my port glass at times, but do agree with the ammonia and "Windex" usage with newspaper tactic due to the wood fibers in the newsprint really scours the glass very well.

Some techs makes up rules as they go along to keep their job by looking important since the majority of the booth personnel don't know what the flip is going on the booths anyway let alone why they are there ...

-Monte
 

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Posted by Demetris Thoupis (Member # 833) on 09-03-2009, 06:38 AM:
 
I concur with newspaper and windex.
 

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Posted by Frank Angel (Member # 248) on 09-03-2009, 01:39 PM:
 
No scientific proof, but on optical glass that is coated, which all good port glass is, I would think newspaper is a bit too abrasive -- after all your are rubbing trees soaked in ink on it. At least it's pretty abrasive before it gets good and soaked.

I would be afraid newspaper, given what it's made of could damage the delicate microcoating, but again, that's just my gut, nothing scientific. I've got a big plastic bag of cloth rags mostly old tee-shirts that I collect as they become worn. I've stored up more than I'll ever use in a lifetime. I use regular lens cleaner and the tee-shirt cloth. I figure if the cleaner is not harmful to coated lenses, it won't be harmful to coated optical port glass. I put it in a spray bottle and just lightly coat the glass where the image passes and then gently wipe clean -- around the rest of the glass if it needs it, I use windex, but again with a cloth wipe.

BTW, I have tried both expensive coated optical glass for the projector port and also Lexan plexiglass and haven't been able to detect any difference at all between the two either in brightness or resolution using the resolution test film. As for the impact of color from plexi, I don't have any instrumentation that can determine that, but to my eye, the white remains as white with the plexi in as it does with it out. That's good enuf for me if the eye can't detect any change. And Lexan is MUCH cheaper than coated optical glass. When you have big ports like we have, using plexi makes a substantial difference.
 

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Posted by Manny Knowles (Member # 1171) on 09-04-2009, 10:33 PM:
 
I used to use a feather duster.

If there was a smudge on the glass, then I'd use plain old water and the folded paper towels from the dispenser over by the sink.

Once in a while there'd be a glass that needed a full-on exorcism and that's when I'd bust out the Bon Ami. "Hasn't scratched yet!"
 

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Posted by Paul Mayer (Member # 355) on 09-04-2009, 11:13 PM:
 
When I was an air traffic controller many years ago, we used newsprint (not newspaper) and Windex to clean the optics in our light guns. Never felt comfortable with using that combination in a projection booth though.

For coated port glass I've always used the same fluid and lens tissue that I use on my lenses - Formula MC. When used properly it does not leave a haze. Haven't found anything that works consistently better, though I admit I haven't experimented lately. Formula MC has been in my expendables box going all the way back to my camera shader days (ah the '70s and those Norelco PC-70s with Angenieux zooms...) Oops. Flashbacks. Old age.
 

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Posted by Randy Stankey (Member # 64) on 09-05-2009, 10:22 AM:
 
For regular port glass...

Windex. Regular, old Windex.

NOT "Potpourri Scented!"
NOT "Lemon Powered!"
NOT "Environmentally Friendly!"

Capital "W". Small "i". Small "n". Small "d". Small "e". Small "x".

Windex! Plain, old, no-frills, blue and comes in a clear plastic bottle with red letters on the label!

Windex! Costs $1.99 at the grocery store.

Just plain, old WINDEX!

***

That is the spiel I had to use after about six months of being in charge of field service at my old job!

The kids would ask what to buy and I would simply say, "Windex" but they would come back with all sorts of odd concoctions! They came back with these "Fresh scent" and "Super Lemon Concentrated" or "Environmental Formula" bottles of crap that did nothing but streak up the windows.

Or, what's worse... They'd go to the hardware store and come back with all manner of chemical cocktails, ranging from paint thinner, to naptha, denatured alcohol and, in one case a kid came back with a container of M.E.K!

If you have optically coated windows, use whatever the manufacturer recommends to clean them with. But, for the run-of-the-mill port windows I've seen in 90% of theaters, there's nothing more effective for the price. There's nothing cheaper and easier to obtain and there is certainly nothing safer to use than Windex.

Just use Windex!

I also agree with those above who say it's not as important WHAT you clean with but HOW you clean.

You can clean with a cloth rag. You can clean with paper towels from the restroom. You can clean with "Bounty" paper towels. Unless the manufacturer recommends something different, even newspaper will work in many cases.

But the number one thing is to use the correct PROCESS!

1. Turn on the light! Don't clean windows in the dark! How can you know if they really are clean?! (Yes! I have seen people do this! )
2. Spray a LIGHT mist of cleaner on the window.
3. Use your towel/cloth to wipe the entire window in order to distribute the cleaner.
4. Wait a few seconds for the cleaner to dissolve the dirt.
5. Use the OTHER side of your towel to wipe off all the dirt and liquid. Make sure you wipe in straight lines. It doesn't matter if you go vertically or side-to-side. Just do it consistently, in an even pattern that doesn't miss any spots.
6. Be sure to get the edges and corners!
7. Take ANOTHER clean, dry towel/cloth and wipe the glass until it is COMPLETELY DRY! Polish it well! This is where you get the glass really clean!
8. When you are done, take your flashlight... (You work in a theater! You have a flashlight in your back pocket! DON'T YOU?!)... Take your flashlight and shine in on the window from an angle to see if there are any streaks or dust specks left behind.
9. If the window is not satisfactorily clean, you might have to repeat the cleaning!
10. In the case where there is oil on the window from the projector, you might have to clean the window two or even three times to get it really clean!

quote: Randy Stankey

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Windex. Regular, old Windex.

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We have removable windows, so we either clean them in the window or we generally have the closer remove all the windows from the porthole and the opener uses "Windex. Regular, old Windex" to clean the windows.

The only constant factor is that Windex cannot, under any circumstance, come in contact with the projector head or lens.
 

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Posted by Monte L Fullmer (Member # 2797) on 09-07-2009, 02:45 AM:
 

quote: Andy Bajew

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with the projector head

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quote:

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For regular port glass...

Windex. Regular, old Windex.

NOT "Potpourri Scented!"
NOT "Lemon Powered!"
NOT "Environmentally Friendly!"

Capital "W". Small "i". Small "n". Small "d". Small "e". Small "x".

Windex! Plain, old, no-frills, blue and comes in a clear plastic bottle with red letters on the label!

Windex! Costs $1.99 at the grocery store.

Just plain, old WINDEX!

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