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How can I tell the difference between a matte white screen, a gain screen, and a 'silver' screen?

Par exemple: I was touring an old dark cinema. At the back of the stage was a screen laced up to two metal poles on either end. The screen looked silver in color with perforations, and appeared to be curved . Whae type of screen are we talking about here? Could it be used today if it is in good condition(except a little dirty)?

The King

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'The King is only as wise as his Jester'

JOE <> Sounds like you have stumbled onto a "Silver" screen... The silver color and that it has been mounted curved just about confirm that... Although they are a must for Polarized 3-D, I am NOT a big fan of silver screens: They tend to "hot spot," are difficult to clean without damaging the silver coating, and almost always need to be curved to help with the light dispersion... IF this is not rotten, dried out, or burned up, is the size you need, and a BARGAIN, it can be taken down, cleaned, re-hung, then re-coated with matte-white, which is the best option for the majority of applications... IF NOT, I would pass...

Hey, Outaframe! Is there a way to recoat the screen? The reason I am asking is that the screen is hanging in a building that I hope to use for my project. It is actually the town's only theater that has been closed for about 20 years. The wood sloped floor is covered with a false flat floor. The stage is intact and is used for live performances. At the back of the stage and behind the original red curtains is a wood backdrop, behind that is the curved silver colored screen. The screen looks to be in good shape other than dust and dirt, is laced up to steel poles, and rests in what appears to be a wood track or guide. I even noticed a Simplex "Sound of the Cinema" speaker in the corner of the stage!

Would I be better off with a new screen, or is it worth saving the old one?

The King

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'The King is only as wise as his Jester'

JOE <> Yes, several years ago I helped restore a solid vinyl silver screen in a BIG old theater that had broken into and had some vandalism... The screen had a couple of large holes, and had spray painted grafitti with red paint... The new owner intended to replace it until he found out what the cost would be... I suggested that we could restore it in matte white, and we did... It came out fine... Since the one you are asking about is in much better shape, and located where you intend to use it, YES it can be done, with the screen hanging... I posted the whole proceedure a couple of months ago on Bigscreen Biz, but if you can't find it, I'll hunt it up for you... First thing you'll need to do is determine what the screen is made of... If it's a fabric screen, rather than solid vinyl, the proceedure and coating material may have to be modified slightly... You may even be able to leave it silver, if you want, depending on how well it cleans up...

JOE <> PS, could that speaker say "Altec, Voice of the Theater" instead of "Simplex, Sound of the Cinema?"...

Yes it actually said 'Simplex'.....something, something. I have a pic on my digi camera. I will post it just as soon as I figure that out. I turned the speaker to the side and it appeared to have a single driver in a large enclosure....mabey it is a subwoofer??? I also noticed a set of about six horns hanging from behind the top center of the screen.

Mabey it said 'sound of the cinema' or voice of the cinema' not sure, but it DID say Simplex. The writing was in script on an up angle.

The King

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'The King is only as wise as his Jester'

JOE <> That script spelling of Simplex makes me think this must be an oldie from the 30's or early 40's... Long before subwolfers were ever heard of, or needed... It could be an Altech with a Simplex logo, as I don't recall that Simplex actually manufactured speakers, but might have sold them... That horn sounds like a multi-cell wide dispersion unit with one driver feeding all the cells (another one that sounds like an old Altech)... Your pictures will tell the tale... These units have a following amoungst "tube lovers" but are really below today's fidelity standards, especially digital sound specs...

You are absolutely correct! You've won a beautiful new.......sorry, just ran out of prizes.

The horn is exactly as you described. It is mounted to the back wall near the ceiling. There is even a speaker wire running to it! Does anyone think I could sell these items to anyone? Mabey some old movie buff?

The King

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'The King is only as wise as his Jester'

JOE <> Yes, depending on the make and model of the horn, and the model of the driver, this could be surprizingly valuable... You might even be able to use it for the center channel of your proposed theater, by adding two more matching horns for the R&L front channels... It all depends on what you actually have there, and the dimensions of your auditorium... The driver will need to be a permanent magnet model, rather than a field coil type, to be of any use to you, but there is a market for the field coil type if you can't use it... Same thing applies to the bass unit in the wooden enclosure... Regardless, hanging speakers high, and far behind the screen is NOT the way to go... IF you plan to use the stage, you will probably need to fly a sound baffle wall, or build one on casters which you can move around... Speakers should be located no higher
than mid-screen height, and as close to the rear of the screen as possible without actually touching it... And they need to be mounted nearly flush in a surround baffle wall that is non sound reflective, to keep sound from bouncing around the backscreen area... This all gets fairly involved, so for now the main thing you need to know is what you actually have there, and the size and shape of the auditorium you intend to end up with...

Quick way to tell if you have a "matte" or "gain" screen. Project "open gate" white light onto the screen (be careful not to damage the lens with excessive radiant energy without allowing cooling time). Hold a sheet of white paper of approximately "90 Brightness" next to the screen, and have someone compare the image brightness.

A "matte" white screen will have about the same reflectance as the white paper, and will not seem to change brightness when viewed from an angle rather than straight-on.

A "gain" screen will look brighter than the paper straight on, but will look less bright when viewed from an angle.

If you want a measure of the "gain", use a screen luminance meter to measure the light reflected from the screen and the paper, straight-on. For example, if your screen measures 16 footlamberts, and the paper measures 10 footlamberts, the gain is approximately 16/10 = 1.6 gain. But measured off angle, the screen will appear darker than the matte paper.

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John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, NY 14650-1922
Telephone: +1 585-477-5325 Cell: +1 585-781-4036 Fax: +1 585-722-7243
E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: http://www.kodak.com/go/motion

John, is there any way to perform this test without the projection equipment? Since the booth is long gone, and the screen is still hanging behind a wooden backdrop, the best I can do is to stick my head in there with a pen light. It *looks* silver. Would this affect the type of lenses and lamphouse I would need, or should I say scrap it and buy new??

Thanks, The King

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'The King is only as wise as his Jester'

Just illuminate the screen with a slide projector, and run the test outlined.

Yes, screen gain will affect how much power you need to meet the requirements of standard SMPTE 196M. A properly curved gain screen can often reduce power requirements in proportion to the gain. But really high gain screens are quite directional, and may be limited to narrower auditoriums.

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John P. Pytlak, Senior Technical Specialist
Customer Technical Services
Entertainment Imaging
Research Labs, Building 69, Room 7525A
Eastman Kodak Company
Rochester, NY 14650-1922
Telephone: +1 585-477-5325 Cell: +1 585-781-4036 Fax: +1 585-722-7243
E-Mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it
Website: http://www.kodak.com/go/motion

[This message has been edited by John Pytlak (edited October 07, 2003).]

Outoframe you can not acceptably repair any screen that has a rip or hole in it and sorry but if one thinks you can then a diservice to the customer is being preformed.
There will always be a shadow around any form of patch
Coating screens need to be sprayed on and no mater what you do sound attinuation will occur due to plugged perferations in the screen

back in the revival of 3D I had to re coat many screens in time for several picture releases in theatres where the owners were to stupid to not place an order for a screen in time to have it delivered and hung for a very specific title and allow manufacturers time to produce it when every one else was demanding one too (much like RED LEDS are right now)
Bottom line you have to have someone with a vacume directly behind the screen to suck out the perfs as the spray is applied

Next throw that simplex speaker in the dumpster
It has a high impedance and in most cases need a bias voltage for the electromagnets
Even if that were not an issue it has poor power handling and definetly no high frequency response

In this day and age with competition to home cinema any exhibitor that doesn't attempt to stay very close to industry standards is in fact hurting the whole industry

Also in a post under the booth I did ask but never got a reply as to what type of processor you are using

GORDON <> I respect your viewpoint, and even though we may disagree on a theoretical level, I do not believe these forums are the place to argue on a personal level... Your viewpoint is that of a seller, installer, and service technician who promotes and benefits from the sale of new equipment... Where money is not an issue, and the business potential justifies the investment, it IS nice to just buy a new one and toss out the one you're replacing... However, some of us here are working in situations which require making use of what we have, and upgrading it to meet new specifications in order to show a profit... With that in mind, I will answer the criticisms you have voiced...

RE, Screen Patching: If CAREFULLY done on the rear of the screen and the perforations are burned back through as I detailed earlier, then the screen is re-coated in matte white with what I indicated, the repairs are not detectable from even fairly close up, and there is no "shadow"... The perforations are not plugged and the screen can be coated using a short nap roller... This was a large screen we repaired, and it saved the guy something like $8,000... I AGREE that re-coating a screen in Silver is an exercise in futility... Even using a spray gun, it's impossible to work fast enough to end up with perfectly even reflectivity using any of the "silver" coatings I have tried...

RE, The Old Horn: We don't even know WHAT it is, as JOE has posted no model numbers, or pictures... I suspect that it PROBABLY is an old Altec, but there is no way of knowing without the numbers, or at least seeing it... IF it is the one I THINK it probably is, and is the correct dispersion angle for his planned use, it IS a very good old horn with a low frequency cutoff of 300hz, and very high efficiency... The driver may, or may not be a field coil model: a few of these (later ones) came with an 8 ohm permanent magnet driver and can be augmented with a tweeter to make an excellent 3 way system... There is a ready market amoungst collectors for the old field coil driver, and modern 8 ohm replacement drivers are available, as are replacement diaphrams... Regardless, it has value, and is not something to just pitch out...

RE, The post on cyan tracks: We had an ongoing disagreement which had run too far already, when you asked about what I used as a processor... Before I had a chance to reply, T Barnes piped in and told me "butt out" in effect, which I did... Since you're asking again, here 'tis... Exciter lamp > Narrow Slit Lens > Kelmer Stereo Solar Cell > Realistic Pro Mixer > DNR adjustable Noise Reduction Unit > NEC Pro-Logic Decoder > 3 huge stereo amps... I also have a sound processor based on the Hughes sound retrival system, which I can switch in to "convert" a mono signal to stereo... Also, a SenSurround "W" Earthquake Horn with 2 - 18" drivers sitting on the auditorium floor and built flush into the wall under the screen, fed by a 24 db/octave Proton active crossover (set at 50 Hz) into one channel of a Cerwin Vega 2200 amp... Screen speakers are 3 way systems I built with Altec 5llA Horns (8 ohm) mids, & 6 Motorola 1005A tweeters... The R&L woofers are corner mounted stuffed labyrinths I built with 2-18" Emenence drivers tuned to 25 Hz... Center channel LF is an old Motiograph large format folded horn (identical to later model RCA) which plays down to 50 Hz and has 2 new 15" Emenence woofers installed... Surrounds are discreet arrays of 4-15" Emenence woofers in closed infinite baffles (built into walls), 12-Pioneer B11EC80 5 1/4" mids, and 12-Motorola 1005A tweeters, each... Every channel will play individually mid-house at 110 DB without clipping, and I can switch the surrounds through that Hughes stereo synthesizer, if I want... System was designed to play flat, but is adjusted to the X-Curve and verified with SPL meter readings... I plan to stay with SR for a while, but am ready to add DTS when I choose to... In the meantime, I have been scouting around for something suitable to make up a red LED exciters with... I have some Luxeon Star LXHL-MD1D's which look like the answer... I'll make up some heatsink mountings which will slip in where my exciters are, and a regulated power supply for them, and I think I will be all set for Cyan tracks, but I still don't like the idea that it's noisier than silver, whether it's 1 DB, or 4 DB, that's NOT an improvement...

First it is not just a sellers perspective
If a patron pays to watch a film that person should not be subjected to corner cutting
I have many discount and reperatory houses that operate on a shoe string budget and would not think of patching a screen.
It is and always will be visable
Also I have always had little use for matte screens

On the Noise reduction issue DNR will not accurately handle SR tracks as it is only a variable lowpass filter