This is topic cleaning reflectors in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by William Dickson (Member # 314) on 04-18-2000, 12:00 PM:
I've read several lamphouse manuals and they all give different ways to clean the reflector. Some say use a dry cloth. Others say lens cleaner and lens tissue. Another says rubbing alcohol and a cotton cloth. What's best? I'd love to hear from John Pytlak on this.
Posted by Gordon McLeod (Member # 33) on 04-18-2000, 12:02 PM:
The best and the safest is what the manufacturer recomends since all of the different coatings can be different
Posted by Jason Burroughs (Member # 68) on 04-18-2000, 01:00 PM:
One thing that I have found that works well on all types of reflectors in rubbing alcoholin a spray bottle and a soft lint free cloth, such as a cloth diaper. No matter how you clean it, 1st thing you should do is remove the bulb. 
then I lightly mist the reflector with the alcohol and in a circular motion start at the center and work my way out. then with a dry portion of the cloth and give it a once over removing any left over streaks.
Posted by Mark Gulbrandsen (Member # 72) on 04-18-2000, 04:28 PM:
One thing I have done many times that works well is to polish alumnized reflectors with Mothers Polish. Its available at your local auto parts store. Alumnizied reflectors are like the ones that come out of ORC lamp houses and consoles. This can make em like new except for the dings, dents and deep scratches. Ultra Flat also makes a reflector polish the works well.
As far as doing dichroics, I would say thet it can't be done properly since the dichroic coating is only several molecules thick. Any polishing and or cleaning would probably change the filtering charasterics of the coating. These can be restored by Ultra Flat or simply replaced.
Hope some of this helps.
Mark
Posted by Pat Moore (Member # 380) on 04-18-2000, 06:23 PM:
Normally the dichroic coating of a reflector should only require a gentle dusting with a soft lint-free cloth. DON'T use paper towels! Stains are best removed with a alcohol or windex if necessary, and use as little as possible. Be sure whatever you clean with leaves no film on the surface -- it will burn into the coating with the lamp running.
Posted by John Pytlak (Member # 331) on 04-19-2000, 05:47 AM:
I agree with Pat Moore that gentle dusting is all that is usually needed. Any haze or "stains" should be removed by gentle wiping with a soft cloth dampened with isopropyl alcohol. Edmund Scientific sells special cleaners and cloths for cleaning delicate optical components. Never use cleaners containing abrasives or ammonia on delicate dichroic coatings. If the lamphouse cooling air intake has a filter, make sure it is clean and effective. Good housekeeping in the booth and a no smoking policy will do wonders to keep optics cleaner.
------------------
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 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Posted by Tim Reed (Member # 137) on 04-19-2000, 06:19 AM:
I never will forget the old timer in KY who, after his first time doing maintenance on one of those new-fangled xenon lamphouses (a Lumex, I believe), said of the yellowish coating: "Well, it took me a couple hours and four boxes of Brillo pads, but I got it off!"------------------
Better Projection Pays!
Posted by Mark Ogden (Member # 43) on 04-20-2000, 01:30 PM:
For a stained or VERY dirty reflector that does not have a dichroic coating, try this: soak a Handi Wipe in water and wring the hell out of it leaving it just slightly damp. Sprinkle a little Bon Ami cleanser on it (the cloth) and rub gently (and ONLY Bon Ami, don't try another powdered style cleanser, else much nashing of teeth and self-kicking of butt will result). Wipe off with another clean damp cloth, followed by dry cloth. This is for seriously munged-up-to-slightly pitted/scratched mirrors only, all else very light mist of lens cleaner on a lint free cloth.
Posted by John Pytlak (Member # 331) on 04-20-2000, 01:45 PM:
Mark:I agree with you that Bon-Ami may be needed for really heavy deposits, but since it is mildly abrasive, it will wear away the dichroic coating with hard or prolonged use. Use it only as a last resort.
I remember their trademark was a baby chick that had the caption: "It hasn't scratched yet".
------------------
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 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Posted by Pat Moore (Member # 380) on 04-20-2000, 03:19 PM:
I'm absolutely with John on this one, but I would go so far as to say NEVER use Bon Ami or similar on a dichroich coated reflector. Bon Ami might be all right when carefully used on an enhanced aluminum or maybe even a rhodium-coated reflector. If a little alcohol and a soft cloth won't get a stain off a dichroic surface, you'r ein trouble.Pat
Posted by William Dickson (Member # 314) on 04-20-2000, 04:57 PM:
How can I tell what type of reflector is in each lamphouse? Our two theaters were hand me downs so there are several different types of lamphouses and we don't have the manuals for all of them.
Posted by Pat Moore (Member # 380) on 04-22-2000, 09:08 AM:
William;
A quick look at the surface of the reflector should tell you. If it's silver, it's most likely an enhanced aluminum, maybe rhodium. If it appears blue-ish or yellow-ish, it's a dichroic cold-coated reflector.
Posted by System Notices (Member # 2357) on 07-21-2006, 12:06 PM:
It has been 2281 days since the last post.
Posted by Iben Jimenez (Member # 3713) on 07-21-2006, 12:06 PM:
Men, A lot of questions...
Well, What is exactly a dichroic mirror? What is the difference between hot, cold, and the different colors of the reflectors?
Thanks
Posted by Gordon McLeod (Member # 33) on 07-21-2006, 12:46 PM:
Simplistically
A cold reflector is the same as a dichroic reflector
The Glass or Metal has a coating that only reflects visable light and the heat is passed through the coating and in the case of a glass reflector out throught the back into the lamphouse so the exhaust removes it. In the case of a metal reflector it is absorbed by the metal and the exhaust cools the metal down
THe colour is the colour temperature of the reflected light which should be around 5400K
Posted by Louis Bornwasser (Member # 3063) on 07-21-2006, 09:13 PM:
Just don't use oven cleaner on metal reflectors like another semi local competitor told his customers. I sold many many new reflectors that year...some of them replaced were only a couple of months old. Louis
Posted by Mike Croaro (Member # 3123) on 07-21-2006, 11:23 PM:
I must be gettting old. I hear everyone speaking of reflectors - in this post and others. I always knew them as "mirrors". Verbiage seems to always change.
Mike
Posted by Charles Greenlee (Member # 3856) on 07-22-2006, 12:49 AM:
At the Carmike 10, we had Knesley and Strong X-90 lamphouses. I don't recall enough detail about the reflectors to tell you whether they were Dichoric or Rhodium, but I think they had a coated look. Not really colored per se, but kind of like they were ever so slightly smoked. I know on the Kneisley's, being older, I'd wipe out the reflector, and my cloth looked like it had glitter on it. Obviously the coating was deteriorating and crumbling off on my rag, I made not of it, but I guess they'll wait until they fail altogether.
Posted by Ian Bailey (Member # 1752) on 07-22-2006, 08:36 PM:
I use a product called SIDOL(French or Italian I think)on my Strong Reflectors with great success.It removes any dirt and haziness on the relector and brings it up like new.You apply it like a metal polish.Wipe it on with a clean cloth,wait till it dries and buff with another clean cloth.
Cheers Ian
Posted by John Pytlak (Member # 331) on 07-24-2006, 10:43 AM:
Cleaning coated (dichroic) optics:
http://www.edmundoptics.com/techSupport/DisplayArticle.cfm?articleid=269