Film-Tech Forum ARCHIVE: Silver screens

This is topic Silver screens in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ron Curran (Member # 3631) on 05-24-2009, 08:12 PM:

Is a silver screen (required for certain 3D systems) similar to the Miracle Mirror Screen that was introduced with CinemaScope?

Also, I seem to remember, when I was a kid, that movies were referred to as the Silver Screen; were any screens silver in the 40s?

Posted by Mark Gulbrandsen (Member # 72) on 05-24-2009, 08:17 PM:

I think it was a lenticuluar screen surface. Silver was only used for 3-D even back then. The CS lenses ate up alot of light and they needed alot of gain back then.
Mark

Posted by Ron Curran (Member # 3631) on 05-24-2009, 09:54 PM:

Thanks Mark (don't you ever sleep?).
We actually had a Miracle Mirror but I can't remember it being lectilinear.
It had to be replaced when the local theatre group destroyed it - served us right for having a framed screen. We then had to resort to a roll-up screen which had to be flat white.

Posted by Monte L Fullmer (Member # 2797) on 05-25-2009, 01:06 AM:

After reading the similar topic in the WideScreenMuseum site:

Wouldn't this type of screen surface be like the old "glass beaded" rollup tripod screens that home projectors used?

Posted by Damien Taylor (Member # 4255) on 05-25-2009, 01:20 AM:

We still have our silver screen. When the theater was tripled in the 80's, All the screen and rigging was brought forward,and the proscenium recreated at the balcony edge. I'm guessing it was from 3D the first time around. But there is definite dark spots, and side visibility is shocking, it has poor gain, and is nearly impossible to clean. But we'll be ready for 3D again [Big Grin]

Posted by Stephen Furley (Member # 1277) on 05-25-2009, 03:57 AM:

This page from the Widescreen Museum:

web page

which seems to be taken from original material published at the time says that they are

'not simply sheets of fabric sprayed with aluminum or other reflecting materials, but they have been embossed with tiny elements, each one of which is so shaped as to reflect light toward the seats in a theatre and to keep it out of waste spaces.'

Of course, 'Not simply' does not mean that they were not silver. However, further down the page it says that these screens are suitable for 3-D. It doesn't say what type of 3-D, but for film, at that time, two strip polarised was the norm, so this seems to indicate that the screens were silver, in addition to the 'millions of tiny "lenses"'. I do remember on an old one which I saw that the joins in the screen showed up badly, and the surface was also badly marked, but it would have been about fifteen years old at the time.

Interesting that it says this:

'20th Century-Fox CinemaScope attractions are available to any exhibitor who can provide a satisfactory projection on whatever screen used.'

I though that the Miracle Mirror, along with the stereophonic sound system was mandatory for Cinemascope. There's no date on this page, maybe it was mandatory at first, but Fox later dropped this requirement, even before they dropped the requirement for stereophonic sound.

Posted by Julio Roberto (Member # 4976) on 05-25-2009, 08:22 AM:

What is being described is what is commonly known as "lenticular" in these situations.

Instead of spray-painting aluminum flakes onto a flat matte white surface to make it "silver", a pattern is embossed into either the substrate or the actual surface.

The silver surface is generally very reflective, and thus offers too much gain to the front, meaning too little (negative) gain to the sides.

The pattern that makes sense to help with this problem is a lenticular one, where the surface is shapped like little (thin) waves running vertically. We don't care about the lack of angle of view vertically, only horizontally, as nobody is looking at the screen from above and the height is usually small compared to the width.

This helps spread light more evenly horizontally across the surface of the screen, helping a bit with the hotspot, the dark corners and the small angle of view. More help can be obtained by curving the screen a bit as well.

Some of the current silver screens are also manufactured of a lenticular kind.

Traditionally, all 3D systems in use in cinema required a silver screen. Exceptions are, of course, the very seldom used Anaglyph systems (i.e. color red/blue glasses) and, much more recently, active glasses systems (some Imax Solido and XpanD) and Dolby (Infitec).

Silver screens were also used for non-3D applications in theaters that wanted to boost the (apparent) light output thanks to the enormous gain they offered. Since the first anamorphic lenses probably sucked up a bit of light, I can see an use in those situations as well.

Due to the reflectivity and inherent color spectrum etc, images usually look very contrasty and saturated (except in the corners if the screen is large, lol), so those could be desirable features to some as well. I'm not going to point out the "not so desirable" features of silver screens .... lenticular or not ... curved or not ...

But for 3D, they were almost mandatory for the longest time. Still are.

Posted by Louis Bornwasser (Member # 3063) on 05-25-2009, 09:17 AM:

Yeh . . . . and when old they are hardly silver. More like dull grey. Louis

Posted by Julio Roberto (Member # 4976) on 05-25-2009, 09:54 AM:

Yeah, they are traditionally a bitch when it comes to aging. They can't really be efectively cleaned. Heck, most shouldn't even been touched. So cross your fingers you don't get stains on them. Some you can clean carefully with a dry cloth. Some can be better cleaned, but those are usually the kind that suck for 3D to begin with ...

Not all silver screens are created equal ...

You can expect them to last about 15 years max before a "mandatory" replacement is in order for 3D applications. If your theatre cares about true presentation quality. Otherwise, you can keep them for 135 years [Roll Eyes]

Posted by Mark Gulbrandsen (Member # 72) on 05-25-2009, 10:03 AM:

There were still a few hanging in the Midwest area in larger theaters that had the tags on them. They were all lenticuluar surfaces. The few locations that did silver for the 80's 3-D re-hash had them painted silver.

Mark

Posted by Dennis Udovich (Member # 1066) on 05-28-2009, 02:48 PM:

If you are using the REAL D 3-D system, then you need a silver screen. Real D does not require the battery glasses required with the other systems. You get disposable glasses. The system works fine, with no need to retrieve the glasses after each show, or cleaning of the glasses. Marcus Theatres has added and/or switched 3D systems to Real D as of tomorrow for UP.

Posted by Gordon McLeod (Member # 33) on 05-28-2009, 06:12 PM:

Miracle Mirror screens were a aluminized (silver) lenticular screen (cloth backed)that was very good on curved frames
Does any one remember the Protolite lensed high gain screens from a few years ago

Posted by Frank Angel (Member # 248) on 05-29-2009, 06:21 AM:

No one manufactures a screen like the lenticular silver Miracle Mirror that was manufactured for Fox for CinemaScope. THAT screen would be ideal for today's conundrum of needing a screen with good characteristics for both 3D and 2D. The non-lenticular silver screens that are used now have all the negatives that silvers are known for when showing standard 2D -- the hotspotting, sometimes severe hotspotting depending on throw and width. Lenticular silvers are the best of both worlds -- they eliminate or at least reduce the hotspotting characteristic of standard silver screens making them well suited for 2D and they maintain polarization do they are good for 3D as well. So how come no one is making them?

I asked a rep at MDI that same question and he said one of the difficulties is that they are not easy to make with a high "unacceptable" rate off the line (funny, they were able to do it for CinemaScope way back in the 50s). He also said that MDI was about to launch a new lenticular silver screen surface. He boasted that the hotspot would be a thing of the past with their product. I don't know if that ever came to pass (I think MDI was bought out or merged or something) and even if they did make such a surface, the question still remains whether or not it really did deal better with hotspotting than conventional silver screens.

Posted by Mark Gulbrandsen (Member # 72) on 05-29-2009, 09:05 AM:

What ever one does if any silver screens are purchased in the near future stay away from the Hurley "washable" silver surface. Its absolute crap and Hurley doesn't stand behind their product any longer!

Mark

Posted by Louis Bornwasser (Member # 3063) on 05-29-2009, 07:01 PM:

Mark; note on the Hurley invoice that they don't warrant anything. . . . not even that a screen is a screen. Louis

Posted by Mark Gulbrandsen (Member # 72) on 05-29-2009, 08:42 PM:

We had other new screens that were defective and they DID replace them but they refused to replace this one. The new silver screen's surface is somehow printed onto the vinyl and it looks like a checkerboard effect! Real crap!

Mark

Posted by Ron Curran (Member # 3631) on 05-29-2009, 08:51 PM:

Thanks Frank, you actually answered the question. I remember images looking excellent on a miracle mirror, except for the joins showing up in extra bright scenes.

They could be, as you said, the solution (sorry Joe) for today.

Surely we could do it better than they did in the 50s.

Posted by Gordon McLeod (Member # 33) on 05-29-2009, 09:29 PM:

mdi is part of STRONG now

Posted by Julio Roberto (Member # 4976) on 05-29-2009, 10:23 PM:

For what it's worth, this is what MDI claims for their "3D" screens:

quote:

Features
• Gain of 2.3 on axis.
• Signal to Noise Ratio (S/N) exceeding 180.
• Excellent performance for 3D projection.
• Can bu used for 2D projection.
• Ideal for digital or 35 mm projection .
• Lenticular surface and reduced hot spotting.
• Seams invisible under normal projection condition.
• Best versatility on the market.
• Quick delivery time

But the should really correct the spelling of the part that goes: "Can bu used" (SIC) [Roll Eyes]

Posted by Mark Gulbrandsen (Member # 72) on 05-30-2009, 08:37 PM:

quote:
Signal to Noise Ratio (S/N) exceeding 180.

Ha! No way... I've heard many an MDI silver screen hiss at me... I'd say no better than 68!

Mark

Posted by Julio Roberto (Member # 4976) on 05-30-2009, 09:02 PM:

I think they were probably referring at the crosstalk performance for 3D rather than sound (i.e. 180:1 polarization maintenance, instead of 180db), but who knows the way the specs are written is not crystal clear, to be honest.

[Shrug]

Posted by Mark Gulbrandsen (Member # 72) on 05-30-2009, 09:26 PM:

Julio...

I'm just kiddin with ya! However I have had screens hiss at me when you take the foam out when the layers unwind... It's dry here with alot of static.

Mark

Posted by Julio Roberto (Member # 4976) on 05-30-2009, 09:30 PM:

[Razz]

Posted by Jack Ondracek (Member # 1466) on 05-30-2009, 10:09 PM:

If they were going to use that kind of comparison, maybe a more correct description would be "crosstalk". ??

Posted by Louis Bornwasser (Member # 3063) on 04-29-2010, 09:02 AM:

Does anyone have experience with silver screens lately (2010)? One vendor versus another?

My experiences are a mixed bag.

This from a guy who spent the last 30 years removing silver screens. Louis

Posted by Sam D. Chavez (Member # 1841) on 04-29-2010, 08:37 PM:

I just bought a 21 x 42 Severtson screen and it was perfect. Not a blemish anywhere and the screen fall off seemed quite good.