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Why 1.85:1 Ratio?


Fiza Chughtai

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Cinema's1.85:1 aspect ratio existed long before 16:9 TVs, and from what I read, was a differentiator to the 4:3 aspect ratio of all TVs back then, without the added cost or complexity of other cinema widescreen formats.

from wiki: When cinema attendance dropped, Hollywood created widescreen aspect ratios in order to differentiate the film industry from TV, with one of the most common being the 1.85:1 ratio

Edited by David Sekanina
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1.85 dates back to the mid-1950's.  Of course, it would now be fairly easy to change the cinema standard from 1.85 to 1.78 as opposed to changing TV sets and HDTV broadcasting.  Some wish HDTV monitors had opted for an even wider 2:1 shape to better accommodate showing both 1.85 and 2.39 movies, though then 1.33/1.37 movies would have used even less of the screen.

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1 hour ago, David Mullen ASC said:

Besides 1.85 vs. 1.78, what's annoying today is the 2048 / 4096 pixel 24P / P3 standards for DCI versus the 1920 / 3840 pixel 23.976P / Rec.709 standards for HD/UHD...

And as TV manufacturers have conflated 4K & UHD, there are many, many producers who don't know the difference.

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The Widescreen Museum has a page on the evolution of wider aspect ratios that were introduced in the 50s:

http://www.widescreenmuseum.com/widescreen/evolution.htm
 

The earliest use of 1.85 was in the Eidoloscope of 1895, a short-lived projection system that probably had no bearing on the decision to implement it again in 1953. 
It’s a curious aspect ratio, with no obvious mathematical derivation - it’s almost 24:13 but not quite, and isn’t one of the ‘square root” rectangles created by the ratio of one to the square root of 2, 3, 4 or 5. 
 

It’s so close visually to 1.78 that we sometimes substitute 1.78 ground glasses in directors viewfinders when the 1.85 ones are all out. I was once asked to mark up a combo groundglass with 1.78 and 1.85 and it just looked like narrow tram lines along the top and bottom edges. I don’t think anyone would complain if 1.85 was relegated to history, except perhaps die-hard traditionalists.

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1.85:1 is equivalent to an integer ratio of 37:20. 

As David points out, it was adopted during the 50's as the studio's were trying to get people back into the theaters during the initial boom of the TV age. One way to do that was through widescreen formats that were generally much wider than 1.85:1. However, as an inexpensive route, many studio's simply shot and projected films with a 1.85:1 matte. Where it didn't deliver the same picture quality as anamorphic 4 perf 35mm, it was a cost savings compared to the anamorphic process. Another thing to note, 1.85: 1 was a US standard first. Much of Europe was still 1.66:1, a format that again, doesn't "naturally" exist like 2.40:1 anamorphic 35mm or 2.20:1 5 perf 70mm, which were the "main" widescreen formats at the time. 

The 1.75:1 aspect ratio is more interesting, quote from wikipedia: 

"
Dr. Kerns H. Powers, a member of the SMPTE Working Group on High-Definition Electronic Production, first proposed the 16:9 (1.77:1) aspect ratio in 1984, when nobody was creating 16:9 videos. The popular choices in 1980 were: 4:3 (based on TV standard's ratio at the time), 15:9 (the European "flat" 1.66:1 ratio), 1.85:1 (the American "flat" ratio) and 2.35:1 (the CinemaScope/Panavision) ratio for anamorphic widescreen."

"Powers cut out rectangles with equal areas, shaped to match each of the popular aspect ratios. When overlapped with their center points aligned, he found that all of those aspect ratio rectangles fit within an outer rectangle with an aspect ratio of 1.77:1 and all of them also covered a smaller common inner rectangle with the same aspect ratio 1.78:1.The value found by Powers is exactly the geometric mean of the extreme aspect ratios, 4:3 and 2.35:1, 47/15≈1.77:1 which is coincidentally close to 16:9. Applying the same geometric mean technique to 16:9 and 4:3 yields an aspect ratio of around 1.5396:1, sometimes approximated as 14:9 (1.55:1), which is likewise used as a compromise between these ratios."

 

 

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13 hours ago, Tyler Purcell said:

15:9 (the European "flat" 1.66:1 ratio)

15:9 is more simply described as 5:3.

Most common cinema aspect ratios are fairly simple ones:  

6:5 (1.20:1)

4:3 (1.33:1) 

11:8 (1.375:1)

3:2 (1.50:1)

5:3 (1.66:1) 

 7:4 (1.75:1)

16:9 or 42:3(1.78:1)

2:1 

11:5 (2.20:1)

But the smallest whole number fraction for 1.85:1 is 37:20. It's a weird choice.

Anamorphic aspect ratios were more often dictated by the amount of space required at the side for a soundtrack while maximising the available height, so for example a 2x desqueeze of 1.33 yielded 2.66, which was then reduced by the soundtrack requirements at the side to 2.35. I can't find any indication that 2.35 or 2.39 were chosen for their mathematical qualities.

I also find it curious that the 'Golden Rectangle' incorporating the magical Phi ratio (1.618:1) was never used, considering how influential it was in painting and architecture over the centuries. Ratios of successive Fibonacci numbers approach Phi ever more closely - 5:3, 8:5, 13:8, 21:13 etc, so mathematically 1.66:1 being a very early Fibonacci ratio (5:3) could be considered as approximating Phi. It's certainly the closest cinema aspect ratio to a Golden Rectangle. 

There were numerous articles in the SMPE (Society of Motion Picture Engineers) journals of the early 1930s discussing possible wider aspect ratios for future film formats, that grappled with such topics as the mathematics of pictorial composition and dynamic rectangles:

1556030054_IMG_0575(1).jpeg.1a5c2422de3ffc817e91fea296004ed1.jpeg

Other articles from that period included statistical studies of famous paintings and their dimensions, and arguments about whether the dynamism of Rubens' paintings made his aspect ratios the most cinematic, but in the end it seems the simplest number ratios prevailed. Except for 1.85, which is neither an aspect ratio common to famous paintings nor an interesting mathematical relationship.

Does anyone know more about the choice of 1.85?

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21 hours ago, John Salim said:

Generally speaking 1.85:1 is a cinema format, whereas 16:9 is a television format.

John S ?

You mean the cinema screen sizes are 1.85 and that is why still movies are shot in 1.85 cause 1.78 will not fit the cinema screen size?

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6 minutes ago, Fiza Chughtai said:

That was the original question too, when it is already too close to 1.78 then what is the need to shoot for 1.85 for current age films

Nothing more than tradition and maybe existing workflows or equipment.

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!.85 is the established cinema aspect ratio, there's only need to use it if you're shooting films for theatrical release. When you're shooting 1.85 you are aware that it's "wider" than !6:9 when composing shots

Can project 16:9 films in a cinema, but they don't feel quite as "wide". A number of productions I've worked on have been projected 16:9, it's not unusual at festivals or special screenings.

Cinemas these days commonly just project on the same size screen, so 2.35 films tend to look less impressive these days, compared to when the tabs opened up to the full width and scope films were projected onto a much larger screen.

 

 

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57 minutes ago, Brian Drysdale said:

!.85 is the established cinema aspect ratio, there's only need to use it if you're shooting films for theatrical release. When you're shooting 1.85 you are aware that it's "wider" than !6:9 when composing shots

If one has to shoot 'wider' than 1.78, they can go for 2:00:1 or 2.39...why go for 1.85 which is hardly any noticeable different than 1.78? In-terms of technical  and aesthetic reasons, not just for the sake of traditions. 

 

 

 

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7 hours ago, Brian Drysdale said:

When you're shooting 1.85 you are aware that it's "wider" than 16:9 when composing shots.

Wider or... lower height. When shooting with the full sensor width, 16:9 uses a greater surface than "17:9" or "DCI"  (other ways to say 1.85:1). However, on mirrorless cameras with high pixel count, the "1.85" ratio, although smaller in surface, might be less downsized than the 16:9, resulting in a "wider" image (4096/2048 vs 3840/1920).

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13 hours ago, Brian Drysdale said:

No one will stop people shooting 2.00:1, it's easier with digital projection than with film projection.

Traditions still occur, especially since some directors like to shoot on film, rather than digital formats.   

 

Based on your given technical reasoning, may you please elaborate;

1. Why 1.85  is easy for Film Projection'? and 2.00:1  and 2.39 are not

2. Even if some directors likes to shoot on film, those films are later Projected in Cinemas Digitally, so what is the hindrance in shooting 2.00:1 or 2.39:1 to get the desired wider aspect which 1.78 does not provides, and makes hardly any difference in 1.85 so why not just opt for 1.78 if does not want as wide as 2.00:1 or 2.39?  > This happens to be my original posted query to know the specific Technical or Creative reasoning to shoot in 1.85 rather just blindly following the tradition.

Edited by Fiza Chughtai
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1 minute ago, Fiza Chughtai said:

1. Why 1.85  is easy for Film Projection'? and 2.00:1  and 2.39 are not

Because 2:1 crops the film so much, there is a demonstrable loss in quality. Might as well shoot anamorphic and crop the sides to get 2:1. 

1 minute ago, Fiza Chughtai said:

2. Even if some directors likes to shoot on film, those films are later Projected in Cinemas Digitally, so what is the hindrance in shooting 2.00:1 or 2.39:1 to get the desired wider aspect which 1.78 does not provides, and makes hardly any difference in 1.85 so why not just opt for 1.78 if does not want as wide as 2.00:1 or 2.39?  > This happens to be my original posted query. 

I mean the optimal for 35mm is anamorphic really. That's going to use the full available frame. Otherwise, any other format is "cropping" the negative. Even with 2 perf or 3 perf, you have a smaller negative than the projection format which is 4 perf. So it's all about "optimal" amount of resolution and 2:1 just doesn't really have any optimization on film. Which on digital, you just adjust the theatrical matte, easy! 

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Cinemas are set up for 1.85:1 projection, as is the workflow and the cameras designed for cinema productions. 16:9 can have slight pillars on either side if you're going through the full 2k DCP workflow,.

If you don't want to shoot 1.85, no one is stopping you shooting 16:9, many low budget films are shot using that aspect ratio. 

 

 

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On 2/20/2021 at 10:54 AM, Dom Jaeger said:

Does anyone know more about the choice of 1.85?

I once did as much research as I could on this for an article, and never really figured that out. Nor did I ever figure out the choice of 35mm width. In that piece I wrote:

Quote

Some sources suggest that it was created by splitting a 2.75” (effectively 70mm) roll film in half; certainly 70mm film had been shot (at the Henley Regatta in the UK) perhaps as early as 1894. Others say that Edison had independently decided on the size and was forced to rather inefficiently cut down 40mm film to suit, although those records fail to state why the 1-3/8” gauge was originally chosen, or why it wouldn’t have made more sense to use the slightly wider rolls as supplied. In those days, splitting commercially-manufactured film rolls into narrower strips to make them go further was common, though in fact the 61mm-wide 120 roll film was actually developed around the same time – in 1901 – specifically to be less expensive than glass plates or large sheets of film. Either way, by the mid-1890s, Edison had arranged to buy film split to his preferred size, laying the foundation for sensor sizing we still use today.

From what I've been able to establish, motion picture production leapt very quickly to something very close to the formats we've used until very recently. The earliest Kinetoscope designs used 1-3/8" (very very nearly 35mm) 4-perf and something very near a silent aperture image.

I was not able to establish where 1.85 came from. It seems obscure.

P

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I always assumed it was just an arbitrary choice, made by some unknown person long ago. The standard was 4 perf 35mm, with the given aspect ratio after allowing for the optical soundtrack. It was then decided a wider screen was desirable in theatres. Too much image cropped on top and bottom resulted in too much image degradation. The aspect ratio was probably decided just by eye. 2:1 was too cropped, and 16:9 wasn't wide enough. So someone just said, "okay, 1.85:1 looks about right .... we'll make it that." In other words it wasn't a mathematically neat proportion, it was just a good creative compromise that worked well. Not too cropped, and just wide enough.

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On 2/21/2021 at 6:11 AM, Satsuki Murashige said:

??

 

Sure, it's easier to picture the shape of an aspect ratio using decimal ratios relative to one.  I was just pointing out the mathematical derivation of most aspect ratios, not promoting a different terminology.  

Though personally I don't have a problem with integer ratios. It just describes the relationship in a different way, and illuminates a different aspect of it. Your position is basically saying that fractions are too confusing and should be replaced with their decimal conversions, but there are good reasons to keep using fractions. Arguing for clarity in communication is a valid stance, but we need to be careful not to end up just dumbing things down.

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10 hours ago, Brian Drysdale said:

Doing some quick maths, it's more or less 2.35 + 1.33 divided by 2 which is 1.84 or 1.85 if rounded up.

That's actually a really good possibility, it was simply the mean of the two most extreme aspect ratios commonly in use. 

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