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Topic: Limited screen size. Should I go CW or CH?

Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-03-2006 06:17 PM

quote: Brad Miller
Plus with curved screens, you lose the apparent width in the aspect ratio, cause geometric distortion and lower contrast. I have also had far better luck with focus on flat screens.

I tend to agree .. seeing 70mm projected on a large flat screen seems to look better than on a curved screen..as long as the downward machine angle wasn't too steep to notice the apparent keystone affect even with trimmed aperture plates..

Thus, if flat screens have better presentations qualities, then why the whoopla on curved screens in this megaplexes then..?

Yes, my cinemas that I work at and service do have the double masking settings..Thus,I have a nice large (1.85/1) flat masking tabs and a decent sized scope (2.35/1) masking tabs..for all my 18 houses in three locations..

-Monte

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Alan Gouger
Jedi Master Film Handler

Posts: 501
From: Bradenton, FL, USA
Registered: Jul 2000

posted 12-03-2006 06:27 PM

Monte

When you say double masking tabs for scope and flat are
you maintaining the same width and bringing in top/bottom masking for scope?

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-03-2006 06:56 PM

quote: Alan Gouger
When you say double masking tabs for scope and flat are
you maintaining the same width and bringing in top/bottom masking for scope?

No..sorry, if I threw a curved ball on this one.

With the actual screen installed and with all tabs open, the ratio is about 2.00/1 - rather wide ratio, but still using a pretty hefty screen size for each auditorium...

When I use FLAT, the top goes up all the way and the sides move in to give me my 1.85/1 ratio.

When I use SCOPE, the top drops down and the sides open up for my 2.35/1 ratio (now, 2.39/1 with a touch on the motor stop tab adjustment for this recommended anamorphic ratio and aperture retrim by tapping on the brass and refile ..)

I've seen theatres that uses 'scissor' maskings - Being the CW type of screens with both upper and lower tabs moving in together for Scope settings.. this keeps the bulb focus in the middle of the screen no matter what aperture cut is used.

Most common practices with machines that are stationary in their tilt settings for each format is to center the bulb on the screen in the SCOPE aperture and masking settings - to get the most of the light out on the screen in this format.

Thus, with the opening of the flat aperture, it's a shade off horizontal center of screen when filing the aperture out if you put an undercut aperture in the machine, and the bulb focus is a bit off horizontal center of screen as well..

Thus, I'd go along with Brad and the most - get the largest screen possible for your home theatre and do the four masking tab stops. You won't be disappointed

[ 12-04-2006, 05:08 AM: Message edited by: Monte L Fullmer ]

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Alan Gouger
Jedi Master Film Handler

Posts: 501
From: Bradenton, FL, USA
Registered: Jul 2000

posted 12-03-2006 08:58 PM

Thanks for the breakdown [Wink]

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Charles Greenlee
Jedi Master Film Handler

Posts: 801
From: Savannah, Ga, U.S.
Registered: Jun 2006

posted 12-04-2006 04:06 AM

Brad, I know I've asked something on this similar subject but please expand on this for me.

quote: Brad Miller
cause geometric distortion

I would thing that light, being projected radially, would be more geometrically correct on a curved screen. And even more so on a concave.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 12-04-2006 08:56 AM

I always favour curved screens
If the theatre has the projector centred on the screen with minimal downward angle the geometry should not be an issue
Also in almost all cases the focus is better as almost all the newer lens are designed for curved screens
Also light distribution on a gain screen is far better

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Louis Bornwasser
Film God

Posts: 4441
From: prospect ky usa
Registered: Mar 2005

posted 12-04-2006 06:22 PM

The focus should not be an issue unless in a very short throw room, whether or not thr screen is curved. As you approach "infinity" (50+ ft) the amount of refocussing required diminishes. Likewise at very short throws, it becomes more critical.

In the days of severe deep curved screens (Cinerama 70) it was sometimes advisable to introduce a magnecom. This allowed the center part of the picture to focus on a more distant plane. Some of the best 70mm I have ever seen was with a really good lens and magnecom, depite the well-known problems with magnecom. Louis

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-04-2006 07:03 PM

You should go for a larger house or add on in the grand screening room style! [Big Grin]

Mark

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Alan Gouger
Jedi Master Film Handler

Posts: 501
From: Bradenton, FL, USA
Registered: Jul 2000

posted 12-04-2006 09:49 PM

Mark that will be my next move in a few more years.

Well heres what Ive decided. Im going with a flat Scope screen. I am able to get an 8 foot wide image end to end but its a tight fit.
I dont know if anyone is familiar with the newer fabric weave screen materials. For reference there is a HT screen company called Screen Research that introduced this new fabric material. Im going with something similar from another company. The gain around 1.3, white, with a weave similar to a speaker grill which will allow me to sit closer not perceive the holes and enjoy the speakers behind the screen.
I should have this next week. Ill snap some pictures and post them as this comes together.

Lots of good information in this thread. I appreciate the help. This is the best film forum.

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Cameron Glendinning
Jedi Master Film Handler

Posts: 845
From: West Ryde, Sydney, NSW Australia
Registered: Dec 2005

posted 12-05-2006 02:44 AM

quote:
The focus should not be an issue unless in a very short throw room, whether or not thr screen is curved. As you approach "infinity" (50 ft) the amount of refocusing required diminishes. Likewise at very short throws, it becomes more critical.

This is what I was referring to with the smaller no of the lens. usually the wider the lens, the closer you are to the screen [Big Grin]

quote: Brad Miller
As far as curved screens, I've never liked them in the first place...but they will look outright dorky on a screen that small.

All I can say is "I wish I had Brads screening room" wow

A few years ago my local watering hole started running pub movies via video, they brought in a deep curve screen probably 8 foot wide. I liked it, made video look kind cinematic in quite a large room(it was Ants that I saw so not to hard on the LCD projector)

Having recently seen Cinerama for the first time, (6 weeks ago) I am very biased to curved screens at the moment.

For the English readers, the Cinema I was referring to with the 50 ft screen, its the Bellevue in Edgeware (top of the northern line)

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 12-05-2006 03:57 AM

Alan, what's that new screen material? Is it competitively priced with standard plastic screens? Can you give us more details plz?

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Alan Gouger
Jedi Master Film Handler

Posts: 501
From: Bradenton, FL, USA
Registered: Jul 2000

posted 12-05-2006 12:36 PM

Frank

Most of the HT screen manufactures offer a AT Fabric screen material. One manufacture goes the expense for THX certification for audio with no need for an EQ but the expense of the license is passed on to the end user.. There are companies who do not bother with the certification that offer an AT screen relatively inexpensive. The problems with these screens are lack of gain. Most measure .85
There is a new company with a brighter white that is rated at 1.3 that offers excellent results. The 1.3 will be the material I have ordered.

I am still very interested in a deep curved screen but want to get my room finished and up and running first so going with the flat for now allows me to finish the room. In time I will do some experimenting and find out just how deep of a curve I can go and if my room and throw allow one that is deep enough for that cool wow factor yet maintaining good focus I will invest in having one made.

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Charles Greenlee
Jedi Master Film Handler

Posts: 801
From: Savannah, Ga, U.S.
Registered: Jun 2006

posted 12-05-2006 10:14 PM

Maybe you can buy the material wide enough to do a curved screen, but somehow roll it around the supports on the sides to take up that extra material until you do go curved. That way you don't have to replace it later.

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 12-06-2006 12:58 AM

Either Hurley, or Harkness Hall has a certain make of screen called a 'microperf' screen designed for home theatre usage. Can't remember which ... - Monte

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 12-06-2006 09:35 AM

micro perf is available from MDI and Lesna as well

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