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This topic comprises 7 pages: 1 2 3 4 5 6 7
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Author
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Topic: Switch from common width to common height - trend or aberation?
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Steve Guttag
We forgot the crackers Gromit!!!
Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 08-09-2007 07:42 PM
In answer to David's statement about being within spec...here is one for you...as per ANSI/SMPTE 196M, Observers should be seated at a distance of 3 picture heights +/- 1 picture height. So if you have a 15-foot tall 1.85 picture, you should be 30-60-feet away. That would probably put you in the last two rows in a typical common width theatre. Certainly most of the seats will not be optimal.
The problem with common width screens for films is that it throws both image resolution and light completely out of whack. You are magnifying the image more for the lower quality image and providing more light for the more light efficient image. How many of you are actually stopping down your scope image so that both Flat and SCOPE are at 16fL? Don't think about refocusing the lamp to compensate for that big a difference, that will bring about other image problems. You could adjust the lamp current, I suppose if the lamp happens to have that range.
The problem is with the design of these theatres to begin with that people feel the need to use common width maskings. The theatres are poorly designed. The width and even the ceiling should have been designed to accommodate a 2.39 screen, period.
When CinemaScope came out...people by and large (though not all) modified the front end of their 4:3 theatres to accommodate Scope. Drive-Ins added to their screen towers for widescreen.
For more research on how to build a theatre correctly, dig up a copy of SMPTE's EG-18. For legal reasons, it was withdrawn but there is nothing in it that wouldn't help an architect properly design a theatre today.
As for stadium seating...that was only an outgrowth of inept theatre design. Patrons didn't want stadium seating, they wanted to have unobstructed views of the screen. Had the sloped floor theatres been properly deisgned (as they used to be), there wouldn't have been a problem to begin with. Just like with sloped floors, this common width screen stupidity is an answer for other mistakes. Fix the mistakes in the theatre design and you will actually fix the problem rather than throw a stupid bandaid on it.
While you are looking up documents, check out the JSMPTE March 1966 issue on pages 179-182. Now there is someone that is actually trying to improve things.
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Jesse Skeen
Phenomenal Film Handler
Posts: 1517
From: Sacramento, CA
Registered: Aug 2000
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posted 08-09-2007 09:52 PM
Although common-height is always the way a screen SHOULD be installed, I would rather have a common-width screen that showed the COMPLETE scope image, since one theater I worked at (now gone) had a common-height screen but for some reason it was installed with about a 2:1 ratio for scope. I don't see how common-width screens give people a reason to go to the theater instead of wait for the DVD, where they'll watch it letterboxed at home.
As I've said before, I'm a firm believer that the screen masking should NEVER change when patrons are in the theater to see it, only exception being if you have 2 movies in the same auditorium with different formats. (That was how I first saw masking change for myself, before I'd entered a projection booth. Ideally in this case it should change the instant the previous movie goes offscreen.) If you're going to show any sort of pre-show material, keep the masking wherever it's going to be for the movie, and size the pre-show on that screen. A lot of theaters with common-width screens are having the masking stay up for the pre-show then go down to scope when the show starts, and this is a bastardization of showmanship. I left my job as booth manager at one theater when I was forced to do this, and I will not work at or patronize any theater that does this. By doing this, you're telling the audience that your precious advertising (which is usually ugly enough on its own) is more important than the movie they paid to see. Also, I tend to sit a couple rows closer if the movie is scope on a top-down screen, and if the masking isn't in place beforehand it's harder to do that. It speaks volumes of the people in charge of many theaters that they know enough about aspect ratios and such to make it "policy" to change the masking for their ad program, but of course not have any policies about keeping the movie properly centered, focused on the screen, and all that stuff.
Since common-width screens are a compromise to begin with, if you're going to have them you should at least make it not so obvious to the average customer. If they don't see the masking move, they might not know that the wider movies are actually smaller on that screen and not care as long as it's presented properly. If it's important for some companies to have their pre-shows on 'the largest screen possible', why the hell do they install common-width screens in the first place???
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Lyle Romer
Phenomenal Film Handler
Posts: 1400
From: Davie, FL, USA
Registered: May 2002
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posted 08-10-2007 05:52 AM
quote: David Zylstra
Unfortunately DCI was seemingly written to economically favor fixed width - i.e. if you have fixed height you need to buy 2 lenses, use a larger lamp and vary lamp power depending on format; but fixed width can be done with 1 lens (all you do is crop 3"-12" of picture).
It was my understanding (I could be wrong) that DC projectors have zoom lenses that can be set to zoom for scope to blow it up for common height screens. That would eliminate needing two lenses.
quote: Jesse Skeen
As I've said before, I'm a firm believer that the screen masking should NEVER change when patrons are in the theater to see it
I couldn't disagree more if you have common height screens. I think the screen getting "bigger" for scope films is great showmanship.
quote: Steve Guttag
As for stadium seating...that was only an outgrowth of inept theatre design. Patrons didn't want stadium seating, they wanted to have unobstructed views of the screen. Had the sloped floor theatres been properly deisgned (as they used to be), there wouldn't have been a problem to begin with.
Wasn't it ADA and the max slope requirements that led to this? i.e. you can't make the slope steep enough for good sight lines and not violate ADA?
Patrons might not have wanted stadium but they want it now. To many "average joe" patrons they wouldn't care if you had the most perfectly desinged slope, they want stadium. My wife can't tell the difference between digital or analog, flat or scope, good picture or bad (unless it's out of focus or excessively jittery) but the one thing she cares about is stadium seating. I could talk till I'm blue in the face about taking her to a properly designed slope theater and she wouldn't care, she wants stadium.
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Steve Guttag
We forgot the crackers Gromit!!!
Posts: 12814
From: Annapolis, MD
Registered: Dec 1999
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posted 08-10-2007 09:28 AM
Well David it is refreshing to see someone that has done his homework and has thought of pleasent ways of expressing their views.
Yes, I was referring to the "review room" standars which are more stringent. Why? Because they are based on how to properly see movies where everyone should be in an ideal seat for proper evaluation (review). The standards for common theatres have to be less strict in order to have enough seats to be profitable. A variation of a mere three screen heights (2, 3 or 4 heights) would keep most theatres with no front rows...which would be better for viewing but would hurt the bottom line. Likewise, for screen illumination...review rooms is 14-18fL versus commercial theatres of 12-22fL.
However, the fact remains, that films viewed at 16fL are seeing the film as the DP/Director and whomever else responsible for the visual content saw it and exposed it and timed it. That is the goal. Likewise for the seating area. This is to allow one to see the detail in the image without seeing the mechanics of it. Sure if you go down to the screen you will see the perfs in the screen, the grain of the film (or the pixels of the image now) but those are the mechanics of the image.
The effect of having the flat image be the this horribly oversized screen (common width) is to bring the mechanics of putting the image back into the observer's vision.
An arguement can be made for DCinema that this is not the case since, like much of DCinema, the quality of the image is less in potential. They have perverted the scope image so that it is indeed the smaller image. There were fewer pixels on the source material as with the projector. If one were to use scissors maskings to merely reduce the height for Scope (with a slight width reduction for flat) then the lens could stay put and the quality of the image would remain constant regardless of ratio...however, Scope was never meant to be just wider but BIGGER...you know "draw em back to the theatres" bigger.
As to rigging. It is indeed true that vertical maskings are more complicated to rig, sorry Chris. A side masking typically is done with just a single cord and minumal pullies (as few as 3 if just pulled from the top). Picture a cord that goes from the machine, up to the top, over a pulley, across the track. At the other end of the track there is another pulley that turns the cord around and sends it clear across the track back to a pulley that sends it down to the masking machine. So you have enough cord such that there are two runs in the track. One run the left half clamps onto, the other the right half clamps onto. So if your masking machine is located on the right, clamp the master carrier(s) to the cord that is coming directly from the machine. Clamp the master carrier(s) for the left half to the cord that has gone through the turn around pulley described above. You now have a system where they part and come together at the same time. Some installers use two master carries for each half to force the leading edge to stay taught for a foot or so regardless of where it is in the travel.
While it may have sounded wordy...it is a relatively simple system that has served masking and even home window shades well for many years.
You can complicate it by also clamping the masking at the bottom with another track as well. There are pros and cons to this but that is for another discussion.
A vertical masking system is another story. You have gravity working against you. In the most simple form you will have a wench type machine that will have a single cord that feeds a clew that in turn feeds several cords that via pullies will raise and lower the upper masking. Presumming the upper masking is made up of soft goods, then it must be rigged to stack up (not flop over the batten). This could get yet more complicated if one were to counter balance the masking with weights (better for the machine since the machine only needs to move the cord and not support the drape too). You can then have top and bottom maksing which will often counterbalance itself but again, gravity must be considered in how to rig the two maskings to move up and down without the rigging being visible.
As for zooming...yes a zoom lens by definition also retains focus as it is zoomed. These are variable focal length lenses. However, these machines have the ability to simulate a zoom by adjusting both the focal length and focus to preset positions. A/V projectors have been doing this for some time...believe it or not it seems to be as simple as putting pots on the lens that "measure" where the desired postions are. The controller merely moves the lens until it arrives at the measured position.
However, Barco, with their DP1500 and DP2000 projectors that are now coming out...they will have lenses that will cover the flat/scope difference (they will have many overlapping lens ranges).
I will have to check but I recall that the DCI spec covered the anamorphic lens thing pretty well and I also distinctly remember that the change between format HAS to be automatic to meet DCI spec (regardless how how it is done).
Lastly, ADA did NOT force stadium seating...in fact it was quite opposed to it as it inherently forces the people they represent to sit only in "selected" areas. Now define which seats are good seats. Well that all depends on the viewer doesn't it? Some like watching from the front row...some the rear some like to watch from the middle most will vary their desire based on the screen size and its relative location to the seats (how high up is the thing). EG-18 actually defined an area based on human head motion and eyesight that would be considered optimal. Take a wild guess where ADA sections were in early stadium seating theatres and where the "preferred" seating areas were as defined on physical facts. EG-18 was pulled rather than get into the legal hassles of what are really architects' poor designs for not following a design that would take into account people actually trying to view the image comfortably.
It is certainly possible to design theatres with sloped floors that have unobstructed views of the screen...exhibitors merely chose not to or their architects didn't do their jobs right. That was the only stigma of sloped floor theatres. If they had the good sight lines, stadium seating would not have been customer driven at all.
An arguement could be made that stadium seating saves on theatre depth as one can stack the rows more tightly and retain good sight lines. However, I've see that go wrong too. However, there is no getting around that stadium seating is inherently mor dangerous in a darkened environment, disliked by most of the elderly and inherently restricts the less mobile.
I'm happy to see that some theatres are compromising...part stadium, part sloped. It seems to give more choice to a varied audience (older and other challenged patrons can be in the easy access sloped portion while younger people can gravitate into the stadium section.
Steve
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![[Eek!]](eek.gif)
. The funny thing here is that Stadium is much more dangerous and accident prone... introduce me to any "Stadium" theater owner that doesn't have at least one "slip and fall" lawsuit going at the moment.
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