235 masking using 2 screens

If you are using motorized curtains and a 1.78 screen to hide the 2.35 screen why not just use the curtains for the masking of the 2.35 screen? Perhaps I don't understand what you are asking?

I don't see how two screens plus curtains would be cheaper then just curtains alone.

Laters,
Jeff

Prices of masking screens if you need an electric screen and can't use a fixed screen are even higher - like 8K + !! You can buy two electric screen - one of them a custom 2.35:1 - for around 1/2 of that!! So in my opinion, yes it is viable. I use 2 electric screens and the zooming method myself.

The 2 screens are about 5" apart. Focus doesn't seem to be an issue. However, I have power zoom and focus anyway, so I can fine tune if need be.

I would ask here about the curtain and gap issue. There seem to be many people with 2.35 systems that use it without any issues. I have not installed any masking on my screen yet so I cannot answer that myself.

What would you do to handle 1.33 material?

Laters,
Jeff

yes masking systems are very expensive. from some companies you can get two or more extra screens for the cost of the masking system. With some small modifications you can make a cheep electric into a nice masking system.

Vutecs systems have always impressed me the most. the material on their Silverstar on is about 1/8 inch from the screen. very nice

There have been posts by some member that has a dowel sewn into the edge of the curtain to provide a nice straight edge...

Mark

Still not a ideal situation when you consider that the curtain edge needs to be 2 to 4" away from the screen to avoid having the pleated material dragging on the screen.

You can get an electronic IR remote controlled masking system that supports up to 10 ar presets (+ full open and full close) from HTIB, or you can buy a combined curtain / masking sytem from them that uses 2 separate tracks, one for the curtain that is spaced far enough away from the screen to avoid dragging on the screen and a second track for the masking that allows the masking to be 1" or so away from the screen.

The two are controlled by the same controller and drive system and probably cost less money than you would pay for the masking option from a commercial screen company (not including the curtain material, of course).

Vern

Why? Here are some pictures:

Curtain fully closed:



Curtain Fully Open:



Curtain open to 2.40:1 preset with projected image:



This is a curved DIY 2.65:1 screen that I built at a cost of ~$200.00 equipped with a combined curtain/masking system with 10 AR presets. Prior to building the new screen, I was using the same curtain/masking system with a 2.55:1 flat screen.

I am not suggesting that you forgo the screen if you need a non-unity gain surface, but the curtain/masking is a totally separate piece of hardware that can be installed to work with any screen, curved or flat.

Vern

Vern, would you please provide the calculation formula for your curved screen?

There is no perfect formula, since the depth of curve of the screen required for optimum pincushion correction is dependent on the throw and the model of anamorphic lens, among other factors.

What I did, as I have described before in other posts was to project a full 1080 x 1920 test pattern. measure the height of the image at the center (edge to edge) of the screen, and use a tape measure positioned vertically at the edges of the picture, moving progressively closer to the projector until the height of the image on the tape measure was the same as the center measured height. Then I measured the distance from this point to the plane of the center of screen which gave me the depth of curve required to perfectly correct the pincushion for my installation. My depth of curve wound up at about 9".

Any other method is a crap shoot.....

Vern