Film-Tech Forum ARCHIVE: Masking Material

This is topic Masking Material in forum Ground Level at Film-Tech Forum ARCHIVE.

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Posted by Ross McLaughlin (Member # 6774) on 03-22-2019, 02:51 PM:

Hi all,
We're looking at installing our own bottom-line fixed masking in a screen, with a scaffold pole to run it over. Is there a particular material that is best to use? It will be directly in front of the sub (if that makes any difference)
Many thanks!

Posted by Gordon McLeod (Member # 33) on 03-23-2019, 05:10 PM:

Black Commando or Duventene

Posted by Marcel Birgelen (Member # 6801) on 03-23-2019, 05:25 PM:

It highly depends on what's available around you, but in general, any high quality blackout cloth will do. Make sure it's permanently frame retardant though and conforms to local fire code.

Posted by Randy Stankey (Member # 64) on 03-23-2019, 08:29 PM:

We used black Duvetyne on the stage where I worked.

Duvetyne is a thin, black cotton cloth, brushed on one side to a suede-like texture. Under blackout conditions, it is opaque but, if there is a light coming from behind, it will show through.

Duvetyne is what I would used in your situation.

Find an example of it, here: https://shop.bmisupply.com/ProductDetail/010608BK054H_Fr-8-Oz-Black-54-Duvetyne--25-Yard

Posted by Marcel Birgelen (Member # 6801) on 03-24-2019, 03:12 PM:

Regarding the subs being behind the masking:

There will be some dampening due to the cloth, but it is probably negligible. Usually, the dampening from those kind of cloths will be mostly in the higher frequency ranges.

If it is possible to run a quick re-calibration after the installation, any kind of dampening can be easily sorted out.

Posted by Randy Stankey (Member # 64) on 03-24-2019, 04:46 PM:

The Duve that I used to work had negligible dampening effects at bass frequencies.

The fabric is as thin as the cotton cloth that people wear as T-shirts and things like that. It is dyed dead-black. It has one side that has been brushed to a texture like suede or velvet. The stuff we used to buy was treated with borax as a flame retardant.

Done with due diligence, using it as a masking over subwoofers will have no effect that an average person can detect by ear. Bass frequencies are so long and the fabric is so thin.

Yes, I agree that it would be wise to do a sound tune-up after you install it but I don't think it's critical.

Duvetyne is the standard fabric that is used in stage theaters to mask off borders of scenery, under platforms and around lights or speakers.

As Gordon said, Commando Cloth is another fabric that is used quite often for the same purpose except it is heavier and it's not brushed like Duve.

Another option that you can try is "shark-tooth scrim."

Scrim is an open weave material that is used for backdrops where you want the material to be translucent when lights shine from behind.

When the lights come from behind, it is see-through. When the lights come from the front, it is opaque. That is a common effect used on stage.

Scrim cloth's open weave makes it almost perfectly transparent to sound but, unless the room is totally dark, you will be able to see through it to the speakers and rigging behind the screen.

It could be a neat effect to use in a cinema. [Wink]

People could see the speakers as they come in to take their seats but, when the lights go down, the speakers disappear.

The down side is that you would have to keep your speakers and the area under the screen clean enough to be seen by the public.

No theater that I ever worked at had an area behind the screen that I would want the public to be able to see! [Eek!]