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This topic comprises 2 pages: 1 2
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Author
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Topic: alternative screen surface
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Peter Murphy
Film Handler
Posts: 2
From: Minneapolis, MN, USA
Registered: Mar 2002
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posted 03-19-2002 03:25 PM
First Entry: Due to the multi-use nature of our space (perf.arts, lectures, symposia, etc), and architectural limitations, we are stuck with a massive (22' X 45') sheetrock wall to project our films on. A commercial screen is out of the question for many reasons, including occassional crowds of adolescent performers, it's vulnerability being a major factor.The new curator of our film program seems to take it as a personal insult that we don't have a "real" screen. It seems to me that the main advantage over a painted rigid surface would be the audio aspect: you can place the speakers behind the perforrated screen and not have that huge wall affecting your acoustics. Image-wise I would think that if you assume that a painted surface has a gain of 1., as John Pyttlak has mentioned, then it's just a matter of applying the appropriate lamp wattage to achieve the industry standard footlamberts (or reasonably close to it). Do to the huge cost invloved in erecting a "real" screen I am loathe to indulge our curator's prejudices in this regard. Other than gain factors I can't believe there's really any qualitative difference between the images on the two surfaces given the correct amount of light for each. I've read some references to painted drive-in screens and painted commercial screens (even one of sheetrock) in the Forums but I'd like to know if there is a recommended screen paint? I know Rosco makes a "super saturated" paint but it is very expensive and I doubt it's much better than standard bright whites. I've recommended to our painters to "find the brightest white you can". Years ago 3M made a special (reflective) screen paint, but it was discontinued. I've heard the suggestion to add some silver paint but I wouldn't think it would mix well with matte white. I'd be curious to hear reactions to this. ------------------ Peter Murphy Media Specialist Walker Art Center Mpls. MN
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John Walsh
Film God
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Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999
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posted 03-19-2002 05:29 PM
How big are the motion-picture images you can project? Do you really use the entire 22' x 45' area? Do you have stereo? Do you mask off the images?To be honest, I'd prefer a "real" screen. If the new curator wants to spend the money, I would be inclined to take it. If you paint the wall, it must be applied evenly, or there will be hot spots. I guess it depends on how much you can spend. If I had only a little money, think I would paint the wall. If I had a more money, I might paint, then install masking to finish off the image. Even more, I'd install a manual roll down screen like Steve suggests. Even more-more money, I might do the manual roll down screen and manual masking. Etc, etc.
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Steve Guttag
We forgot the crackers Gromit!!!
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Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 03-19-2002 08:00 PM
There is no substitute for the speakers behind the screen. One has to consider the time-delay on the sound. In Jerry's idea, the time-delay gets even worse. There is also the extreme dislocation of the dialog from the actor's voice vs what we see on the screen.I just worked on a theatre where the decision was made to use the cluster speakers instead of dealing with speakers behind a, in this case, roll down screen. The results....SO many complaints that speakers are now going to go behind the screen. As to the question at hand. There is no substitute for a good screen, period. A wall is a wall, not a screen though they certainly have been used for screens. I'm with the others that recommend coming up with a removable screen of some sort, (in order of preference)...Fly the screen/masking system if the rigging permits, electric roll down (VERY EXPENSIVE for a good one), Scenic roller, not as expensive as you might think. Steve ------------------ "Old projectionists never die, they just changeover!"
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Peter Murphy
Film Handler
Posts: 2
From: Minneapolis, MN, USA
Registered: Mar 2002
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posted 03-20-2002 11:13 AM
Thanks for your responses. Our space, built strictly as a lecture hall, is more of a theater simulation than an actual one. We are a non-profit institution with too few dollars chasing too many needs. Resourcefulness and making do are the standard modus operandi. Scarce funds spent on something that can so far only be justified as a "preference" must compete with more basic crying needs. For instance, I would rather upgrade our lamphouses which are old Xetron XTN-4000's bought used in the 80's, built in the 70's. We have horrendous acoustics. (The architect must have failed Theater design 101). Some major attention needs to be put into that. Isle lighting is ridiculous. The wall has always been used for projection. Streaking and bloching aren't a problem. We do not use the entire wall for film screenings. Our cinemascope image is 37' wide. There is no masking, though we do have manually operated curtains. The practicality factors stack up against us. Fast turnaround times are sometimes demanded. Programs can include combinations of film and live performers. Fast fold screens are really not all that "fast" (and would require more than one person. I'm not sure even a rollup screen would be workable. It is unlikely that our great wall will ever be demolished which negates the option of behind-the-screen speakers. There is zero fly space. If anything a screen could (as suggested) be unrolled in front. We have a very steep slope on the seats. We are equipped for Dolby (SR). The speakers are currently tucked near the ceiling at the top of the screen. Directionality doesn't seem to be a huge problem but if the acoustics were improved that may become more noticeable. Considering the expense the benefits seem marginal. I was hoping for a little more hard science here -- the physics of vinyl vs. matte paint. Does it somehow magically bring out detail in the dark areas or something? I mean isn't paint these days pretty much made out of plastic? How different can it be? We're just trying to reflect white light here. I've always thought our images look pretty good up against commercial screens. Perforations actually sacrifice a considerable amount of your light.
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Randy Stankey
Film God
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Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99
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posted 03-20-2002 11:04 PM
Peter,I know what you go through. I'm the Tech. Director at a college performing arts center here in Erie, PA. (825 seats) Sometimes you feel like you're shoveling shit against the tide. We're lucky to have an administration who wants to have a quality film program. The mission statement for the film series is, "To show movies that don't come to the local megaplexes and to provide a superior presentation." However, that doesn't mean we don't have to fart around to do it. Just tonight we are showing a film right in the middle of "tech week" of another performance on the stage... Stravinsky's "Soldier's Tale" and Menotti's "The Manticore and the Unicorn". The stage is set up with platforms/risers and backdrops. There's no room to put the speakers on stage. (Behind the flown-in perf. screen.) We have to move some of the set pieces out of the way, only to move them back before leaving tonight. There's probably at LEAST 4 hours of tech time to make final tweaks to the light cues, etc before we have to be ready for a show at 10 AM (for the local school kids) Then there's the "Go Show" Friday night. All this work just to strike EVERYTHING before Monday because tech week starts all over again for another production... The opera, "La Boheme". Both of these shows are using video back-projection for background imagery PLUS the opera is going to have "super-titles" projected on a screen above the proscenium. If I work 12 hours a day, I'm lucky to be going home early! ![](http://www.film-tech.com/ubb/eek.gif) Hit me with an e-mail if you want to chat about stuff or comiserate. ![](http://www.film-tech.com/ubb/wink.gif) (rstankey@mercyhurst.edu)
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Frank Angel
Film God
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Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999
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posted 03-21-2002 09:41 PM
Ah, non-profit performing arts. How DO we do it?!!.... that trick of making a purse out of a sow's ear? Could it be by working 60 hour weeks? Randy, I commiserate with you!Peter, FIX THE ACOUSTICS FIRST! The picture will look fine on a wall or a screen or a sheet as long as the surface is painted with white-white flat paint and it is smooth. I once made a screen on stretched muslin over a frame the carpentry shop built at a local high school --painted it with pretty cheap flat ceiling paint. The paint made it sag and I thought all was lost -- then the paint dried, the muslin shrunk and stretched tighter than the skin on a kettle drum. It looked great. But speech intelligibility -- now THERE's the rub. It is going to be the biggest problem if what you say is true about the acoustics. This has to be a big room, right? The fact that you can't put the speakers behind the screen probably won't be as big a problem as Steve and Mark might think -- our theatre was designed with an acoustic chamber above the stage that projects sound to the audience and there was never any other way to do it -- behind the screen was not an option. We have to live with them in the "speaker loft," but the result isn't as disagreeable as you might think. I disagree that this makes it impossible to make actor's voices localize at the screen -- this is never the problem; the problem is wall reflections that ruin intelligibly in many areas of the theatre, especially the side walls. Buy cheap paint instead of a screen and save your money for deadening reflections (you are going to be buying and hanging lots and lots of velour material). Yes, today screen surfaces, especially the pearlescant surfaces that you will find offered by Technikote or Hurley, can give you increased gain equally over the visible light spectrum, not adding or subtracting intensity at certain frequencies. BUT the surface which consists of microscopic reflective "bubbles" is easily damaged and would be foolish to put it in the harms way of adolescents. Paint and your wall will do you well. Someplace I have the results of some tests the folks on the Drive-In forums did and the paint brands and formulations that produced the "whitest" white. They also had a process in which they paint first with a coat of flat white, then spray a light coating of silver paint, then spray that with another light coating of white. If I can find that info, I will post it. Also, if there is any way to design a mask, that also will go a long way to making an image look professional and really theatrical. I once saw a system where only a small strip of black, maybe a three feet wide, was used for the each of the side masks. The strips were mounted on a very light-weight track almost flush up against the main curtain track. The front of the mask runner was attached to the main curtain runner with thin aircraft cable and when the curtain opened, it simply pulled the mask along with it. Where ever the curtain stopped, the mask remained about a foot in front of it, perfectly masking the picture. When the curtain closed, it dragged the mask piece behind it. Quite ingenious. The need for this was promped by the fact that they couldn't mount another traveler track heavy enough to hold a full expanse of mask material. Using only a few feet of black mask material enabled them to use a lightweight household track and runners. Imagination can sometimes be worth it's weight in gold.
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