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Are projectors and 2-perf 2.35:1 or 2.39:1


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#1 Lindsay Mann

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Posted 11 March 2008 - 09:25 PM

A friend showed me around Technicolor, New York the other day and the subject of 2-perf came up. He told me he keeps seeing people frame for 2.35:1 rather than 2.39:1, which he says is what most theater projectors frame for. I keep reading different specs on the 2-perf system. So which is it? 2.35:1 or 2.39:1?

And if it's both, can someone help me understand that?

And on that note, doesn't 2-perf present a challenge for some special effects because there's less information in the negative?
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#2 Chris Keth

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Posted 11 March 2008 - 09:31 PM

As far as I know, 2-perf is still 2.39:1 just like anamorphic 35 is. I don't really know why it (and anamorphic) is sometimes quoted as 2.35:1 or 2.40:1 (though the latter could be simple rounding off)

Edit: I kind of answered my own question. A quote from the widescreen museum (www.widescreenmuseum.com) pages on cinemascope:

"The height of the CinemaScope image on film, (and all other clone systems), leaves no room between frames. Consequently, splices, both done in the lab and and in the theatre, would cause flashes of light at the top or bottom, or both, of the picture. Theatres took to masking the 2.35:1 frame down slightly to cover the splices. In 1970, the SMPTE set an "official" standard that reduced the height of the projector aperture to conform to the general practice that had been in use for several years. While 2.39:1 is a wider ratio than 2.35:1, the change represents a reduction in height not an increase in width."

Edited by Chris Keth, 11 March 2008 - 09:35 PM.

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#3 Saul Rodgar

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Posted 11 March 2008 - 10:51 PM

And on that note, doesn't 2-perf present a challenge for some special effects because there's less information in the negative?



These days a good 2k + film scanner should give you enough info for most post efx work, something like a Spirit or better. A 4k scanner definitely would give you loads of pixels. In fact, the renaissance of 2 perf is largely due to the advent of 2k film scanners since the main drawback of using it back in the day was the extra optical printing process that would soften and add grain to the picture, which is now a thing of the past with the use of DI's.

What can really be a problem I think is that the gate MUST be absolutely clean of hairs, debris or emulsion buildup for 2 perf to work well since there is not enough space between the edge of the camera frame and the projection frame edge. I recently saw a bunch of new release prints of Spagetti Western faves, and I was strartled by the sheer amount of foreign artifacts on the edge of the frame. I would lose track of them usually after counting more than fifteen single instances of hair on the camera gate during a single movie . . .
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#4 Saul Rodgar

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Posted 11 March 2008 - 11:22 PM

A friend showed me around Technicolor, New York the other day and the subject of 2-perf came up. He told me he keeps seeing people frame for 2.35:1 rather than 2.39:1, which he says is what most theater projectors frame for. I keep reading different specs on the 2-perf system. So which is it? 2.35:1 or 2.39:1?


As far as projectors goes, theatrical 2 perf 35 mm prints do not exist, that I am aware of, nor do I have not heard of any 3 perf 35mm prints for that matter. See, 99.99% of commercial 35 mm projectors pull film down after 4 sprocket holes, so they would have to be modified to run 2 and 3 perf prints. Otherwise the framing would be off at best, and other strange things would be seen. AND it is impossible for most cinemas to have multiple projectors for different prints. Regardless of how they were shot, commercial 35 mm widescreen prints are all anamorphic 4 perf these days, with some anamorphic 16 mm prints used mainly 30 years ago.

And the aspect ratio is dependent on what anamorphic lens you have on the projector. The movie theatre where I help out has a 2.35:1 lens, but I think you can ask the distributor for different squeeze ratios on the print depending on the lens you have, if available . . .

What you have to realize is that film distro houses have to make it easy for cinemas around the world to project their prints, so that means using mainly the 4 perf 35mm standard; unless they are going 70mm or IMAX or something like that, in which case things are obviously different.
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#5 David Mullen ASC

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Posted 12 March 2008 - 12:12 AM

All anamorphic projector lenses for 35mm scope prints have the same squeeze ratio: 2:1, or 2X.

What makes the image 2.35 or 2.39 once unsqueezed is not the squeeze ratio of the lens, it's the shape of the projector mask.

Current ANSI standards for scope projection is 2.39 : 1, so that's what framelines in cameras shooting for scope projection should be set for.

The projector mask should be .825" x .690" (20.96mm x 17.53mm). This works out to be an aspect ratio of 1.195652 : 1. Since the image has a 2X optical squeeze, this becomes 2.3913 : 1 when doubled in width by 2X optically, by the anamorphic projector lens.
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#6 Hal Smith

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Posted 12 March 2008 - 08:59 AM

................. Regardless of how they were shot, commercial 35 mm widescreen prints are all anamorphic 4 perf these days.............

NO!!!

Commercial release prints are either 1.85 "flat" or 2.40 "scope". Every theater is set up to project either format. This is so prevalent that trailers come in two aspect ratios, scope and flat. That is so that if a given house is showing a flat feature that every trailer spliced in is flat regardless of the distribution format of the trailer's feature itself. Conversely a house showing a scope feature has its trailers in scope regardless of the distribution format of those features.

There are a few projectors with lens turret head accessories (sort of a giant two holed version of an Arri 2 turret) that can switch on the fly but they're very much the exception.
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#7 Saul Rodgar

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Posted 12 March 2008 - 11:01 AM

NO!!!

Commercial release prints are either 1.85 "flat" or 2.40 "scope". Every theater is set up to project either format. This is so prevalent that trailers come in two aspect ratios, scope and flat. That is so that if a given house is showing a flat feature that every trailer spliced in is flat regardless of the distribution format of the trailer's feature itself. Conversely a house showing a scope feature has its trailers in scope regardless of the distribution format of those features.

There are a few projectors with lens turret head accessories (sort of a giant two holed version of an Arri 2 turret) that can switch on the fly but they're very much the exception.


YES!!!
The projection format depends on the lens you use to project. With "flat" you use a non-squeezed lens and unmask the screen. With "scope" you get your anamorphic unsqueezed lens and mask the screen.
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#8 Saul Rodgar

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Posted 12 March 2008 - 11:14 AM

Correction:

YES!!!
The projection format depends on the lens you use to project. With "flat" you use a non-squeezed lens and unmask the screen. With "scope" you get your anamorphic unsqueezing lens and mask the screen.


Regardless of what lens you use the movement is 4-perf 35mm. The reason it looks squeezed when you mix flat and scope on the trailers is because they didn't change the lens. Impossible to do without the projector being stopped. And I was talking about widescreen 35mm, 1.85:1 35mm is not considered widescreen.

Did you even read my post?
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#9 John Sprung

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Posted 12 March 2008 - 01:12 PM

The reason it looks squeezed when you mix flat and scope on the trailers is because they didn't change the lens. Impossible to do without the projector being stopped.

Impossible in a single projector platter house, but in a changeover house, you could set one machine up to run the scope reel, and the other flat. Much more convenient if you have a three machine booth, you can have two set up for the feature and the other for trailers in the other format.




-- J.S.
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#10 Saul Rodgar

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Posted 12 March 2008 - 01:43 PM

Impossible in a single projector platter house, but in a changeover house, you could set one machine up to run the scope reel, and the other flat. Much more convenient if you have a three machine booth, you can have two set up for the feature and the other for trailers in the other format.




-- J.S.


John, you are right. I help out at a single projector platter cinema and the booth is tiny and taken over by the 35mm and 16mm projectors, platter and rewind table. Sometimes I forget there are multiple 35mm projector houses!
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#11 Leo Anthony Vale

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Posted 12 March 2008 - 01:52 PM

And I was talking about widescreen 35mm, 1.85:1 35mm is not considered widescreen.


& fellatio is not considered sex by today's youth.

Yet 1.85:1 is widescreen. It's insidious, the widescreen format that pretends it's not widescreen.

http://widescreenmus...aspectratio.htm

Also from the Widescreenmuseum:

"In the early 1950s, studios did begin to compose their movies so that the top and bottom of the picture could be chopped off and a wider screen would show the center of the old 1.37:1 frame. The aspect ratio used by the various studios varied from about 1.5:1 up to the common 1.85:1."

--- http://widescreenmus...creen/intro.htm

Italian movies used to advertise 1.85:1 as Panoramica
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#12 John Holland

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Posted 12 March 2008 - 02:00 PM

Brilliant post Leo and so correct .
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#13 Saul Rodgar

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Posted 12 March 2008 - 02:58 PM

Yet 1.85:1 is widescreen. It's insidious, the widescreen format that pretends it's not widescreen.

http://widescreenmus...aspectratio.htm


OK, TODAY there are two commercial 35mm formats in use. 1.85:1 and 2.35:1/ 2.40:1

1.85:1 is considered TODAY the non-widescreen of the two. Did I say that in the past 1.85:1 was not considered widescreen? It just so happens that 1.37:1 35mm is not used commercially much anymore, if at all.

What is with the "we'll teach the young snotty ones a lesson" attitude, anyway?
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#14 Matt Kelly

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Posted 13 March 2008 - 12:49 AM

What is with the "we'll teach the young snotty ones a lesson" attitude, anyway?



Haha... i think it stems from the incredible trend of people making posts on topics that they claim to be well versed in... but really arent...I know I've been guilty of it before. :blink:

Young Snotty Question: ANSI standards changed at one point from mainly 2.35 to mainly 2.4, right? I was under the impression that it was Panavision's taking over of the anamorphic format that did this, but why? Do they use an ever-so-slightly higher optical compression, or is it still strictly and technically 2:1 in their anamorphics?
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#15 David Mullen ASC

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Posted 13 March 2008 - 11:52 AM

And I was talking about widescreen 35mm, 1.85:1 35mm is not considered widescreen.


Yes. 1.85 is definitely considered widescreen.

1.37 Academy is not widescreen, then the Widescreen Revolution of the 1950's created formats like matted widescreen (1.66, 1.85, etc.) and anamorphic widescreen (CinemaScope, etc.)
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#16 David Mullen ASC

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Posted 13 March 2008 - 11:59 AM

Haha... i think it stems from the incredible trend of people making posts on topics that they claim to be well versed in... but really arent...I know I've been guilty of it before. :blink:

Young Snotty Question: ANSI standards changed at one point from mainly 2.35 to mainly 2.4, right? I was under the impression that it was Panavision's taking over of the anamorphic format that did this, but why? Do they use an ever-so-slightly higher optical compression, or is it still strictly and technically 2:1 in their anamorphics?


35mm scope projection starting with CinemaScope has always been 2X. The changes in shape using 2X anamorphic projector have all been due to the shape of the projector aperture.

Originally CinemaScope was going to be 2.66 : 1 (silent 1.33 full aperture projection with a 2X lens and separate interlocked sound, like Cinerama used.) Then they decided to make special print stock with smaller perfs (CS perfs) and magnetic soundtrack stripes on each side that trimmed the width to 2.55 : 1, and centered on the negative, which is why contact prints of early CinemaScope movies like "20 Thousand Leagues Under the Sea" now look offset.

Then they went to standard perfs and an optical soundtrack on the left, like like for Academy and 1.85 movies. This shifted the optical center to the right and trimmed the width further to 2.35.

Then in the early 1970's, a decision was made to make the projector aperture less tall to hide the negative splices better, which were causing frameline flashes on screen. This trimmed the 2.35 image vertically to 2.39. Then at some point in the early 1980's, the overall size was changed again, I think slightly smaller all over, which kept the 2.39 shape.

But the squeeze ratio has always been 2X.
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#17 Saul Rodgar

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Posted 13 March 2008 - 12:46 PM

Haha... i think it stems from the incredible trend of people making posts on topics that they claim to be well versed in... but really arent...I know I've been guilty of it before. :blink:


Well, if that is the case we all deserve to be talked down to. Show me someone who knows everything, of all the things that can be known in the universe, or the field of cinematography in this case?

If the right of posting in this or any forum was dependent on being absolutely right, only two or three people could post at any given time, if that.

The true value of argumentative speech in a free democratic society is that while some people know more than others, we ALL deserve respect for our opinions, however wrong they may be. I never claimed to have all the right answers to all or any of the questions herein. Freedom of speech does not include the right to scorn others.

Respectful disagreement with someone else's opinions is one thing, contemptuous and derisive "I know more than you do" attitude is another.

This is a SAD trend I see happening all over this forum (which reflects a much larger trend in general society), self-righteous members who feel the need to put down other members' opinions for things like their age or level of technical knowledge, or just because.

It is the nature of the beast I guess, being that words are typed on computers as opposed to spoken to someone directly. In post-high school real life, most people would be more conservative with their attitude, since it could result in a physical confrontation. But in the virtual world, one can type just about anything and get away with it . . .

Edited by Saul Rodgar, 13 March 2008 - 12:51 PM.

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#18 Phil Rhodes

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Posted 13 March 2008 - 01:57 PM

1.85:1 is colloquially called "widescreen" by most UK projectionists, at least, to differentiate it from "scope" (for cinemascope). The cans themselves are usually marked "flat" or "scope".

Phil
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#19 David Mullen ASC

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Posted 13 March 2008 - 02:33 PM

Saul, first you said incorrectly that all widescreen prints are anamorphic, and then you followed that up by incorrectly correcting someone by saying that 1.85 was not widescreen.

It was your superior attitude that caused other people to project an even more superior "attitude" in response. That doesn't make it right --- we should all try to correct people politely -- it's just that often it's a two-way street: it's not everyone else's responsibility to behave more humbly and with deference so you can continue to behave however you want.

People were "taking the piss" out of you, and it's not pleasant of course, but you sort of put a target on yourself by being so adamant about your inaccuracies, so people became more aggressive (than normal) about correcting you.

Let's all step back now and start from scratch...
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#20 Michael Nash

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Posted 13 March 2008 - 03:59 PM

Let's all step back now and start from scratch...


Okay... I try to avoid confusing terms like "widescreen" altogether if I know it might be misinterpreted. But then I don't work as a projectionist, so I don't have to deal with it.

And don't even get me started on the whole public confusion between "anamorphic" films (2.39:1) and "anamorphic video" DVD's...
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