Does anyone have a solution for keeping this glass clean.
 

There's just something about those McDonald's napkins that works wonders on optical glass. However you must have the sanding block to do a good job. Don't try and use other kinds of napkins, as McDonald's has the only good ones for this job. The lens cleaner will get off that baked on cheap glass cleaner residue. When you are done, you will not be able to tell there is glass in the window frame.

Oh yes, since this topic is in regards to film projection, I am moving it to the Film Handler's Forum.

BTW, Kim-wipes are lint free cleaning tissues that work well cleaning port glass.
 

Seriously though, next time you're there grab a stack of their napkins. You'll be amazed!
 

I've had the same problem with scratched plexiglass ports. My solution was to go to a glass store and buy four 13.5" square (for 12" square ports) pieces of picture-frame glass. Total cost was about $7. You really only need to replace the ports in front of the projector lenses, but I like to be able to have a clear view of the screen for focusing.

I will add that this was the best $7 I ever spent on booth supplies (since I was working for people who were too cheap to reimburse me for such things)... There was a big improvement in brightness and sharpness--much more than I would have expected, given the Kollmorgen Super Snaplites we were using.

Optical glass would be better, of course, but that's expensive and hard to find and maybe not really worthwhile unless you have ISCO or Schneider lenses (or anything else that's similarly good).
 

I put two similar pieces in an old booth, and to be frank, I didn't notice any earth shattering difference from the plain float glass that was being used. I suspect that a coated glass would be an improvement, but I remember doing some calcs about that time and being amazed at how forgiving the projected beam was even a foot or so out of the lens, and how plexiglas had a lower refractive index and (if flat) made a better choice than glass. (John P. do you have any references?)

I 'spoze I should sell the glass. It has been cluttering a shelf for over 25 years (still in the original manila envelopes).

 

I've tried everything I could think of...

Denatured Alcohol. -- Dissolves the dirt but it dries too fast before you can completely remove the dirt and leaves residue.

Lens cleaner. -- Didn't dissolve the dirt well enough. (But I will try again, using Brad's "secret weapon")

Isopropyl Alcohol. -- The common garden variety (70% or 90%) does okay but you have to work fast or it'll dry up too. Then the alcohol dries faster than the water and that leaves streaks if you don't dry it up before the alcohol is gone.

Pure, "anhydrous" isopropyl alcohol. -- See denatured alcohol, above.

Various "industrial" cleaner/degreasers, like "carbon-tet", tricloroethane, acetone... you name it. -- I tried a small patch in one corner, first. I just took one look and quit. It makes it worse. Just don't go there! I don't even know why I tried, except out of desperation. (How did I get my hands on that kind of stuff? Don't ask questions that'll get somebody into trouble, okay.)

The only thing that I have found that does a half-decent job is Windex®. Not Glass Plus. Not "lemon-scented... Not "no-drip"... Not "potpourri fresh"... Just plain, old-fashioned, ordinary Windex-with-a-"W".... Windex!

I found that you must use the MINIMUM amount to wet the window. Maybe even just one squirt if that's all you need. Any more and you just make a big mess. Spread the liquid evenly over the window with the first paper towel. Flip it over and wipe it clean, then get another DRY paper towel and WIPE LIKE HELL until it's completely dry!

This is the only thing that I have tried that even does a "passable" job, but you have to work up a sweat to do it right. Do that every day for a week in a 17-screener and you can loose some weight!

It's a breath of fresh air to hear of this solution! You can bet that tomorrow, on my way to my next theatre, I'm going to Mickey-D's and then to Sears!

I haven't darkened the doorstep of a Mickey-D's in such a long time I can't even remember. The food down South is so good I'd probably hurl from the crap.

I guess everybody has to "Take one for the team" every once in a while!
 

F.Y.I. I've always used Rosco lens cleaner, but my preference is Kodak for personal use. Unfortunately the Kodak stuff is more expensive and most theaters will not buy it.
 

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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
 

I smeared glass with popcorn oil, dust, dirt, etc. then cleaned the glass with various cleaners and did a side by side comparison of the results.

IIRC I tried about a dozen types of glass cleaners, ammonia, iso alcohol, wiping with newspaper, wiping with paper towels, etc.

The best product _by far_ was the aerosol can of "Misty" glass cleaner by Amrep, out of Atlanta. The reputation of the product predated my test by a number of years. I remember Cowboy of P&W complaining that Misty shouldn't be sprayed inside projectors, long before I knew what or who "Misty" was. I'm sure Misty would rip the coating off lenses, so I see Cowboy's point.

BTW, if you want to have some fun with customers, do a glass cleaner test like I did, by smearing crud on the front doors of the lobby in the middle of the day. You'll get some interesting double takes and comments.

1) Bounty and Windex (no substitutions)

2) 1 cup vinegar : 1 gallon water , squeegee dry and mop up the runoff

Optical glass can look really good, just don't go for the double-paned soundproof crap they put in my booth! Its quite a maneuver to clean between the pains (sic) .
 

The portglass for the Phoenix and a few other theatres i have worked with came from there.

Aaron

By the way, I'm wondering whether the napkins are the same at every McDonald's around the world. Ours have a checkerboard pattern with the 'M' logo on it. Very smooth. Is it a match? (Wish I had a digital camera!).

The idea of going vertically on one side and horizontally on the other is very innovative. Got to hand it to you, Brad!
 

Next, the optical coatings really do work and are a benefit in many ways. First you don't waste as much light on the glass and more goes through. With double ports this also helps keep multiple images down.

Double ports should become the standard. A single pain just isn't enough to keep the film noise down. The better designed ports make cleaning both pieces quite easy from within the booth (no ladders).

Steve

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"Old projectionists never die, they just changeover!"
 

Of course, you are correct by not cleaning a lense any more than necessary.

Oh, by the way - when I clean lenses, I use two or three thicknesses so that any oil that may be on my fingers will not soak through and get on the lense, especially if I have to use lense cleaning fluid. Some may think it is a waste, but I don't.

I haven't used the McDonald's napkins yet, but I have used those brown paper towels first with rubbing alcohol, followed up with dry towels. Lots of wiping to do, but the results were very good.