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Matching subjective graininess between smaller and larger frame sizes via overexposure?


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#1 Karim D. Ghantous

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Posted 09 February 2018 - 09:18 PM

Let's take two frames, taken on the same film stock. One is 2-perf, the other is S35 anamorphic. For the sake of argument, the aspect ratios are the same, and the S35 frame is double the surface area of the 2-perf frame. You expose each frame to the same scene.

 

Of course, if you are enlarging each frame to fit the same screen size, the anamorphic frame will show less graininess, especially in the shadows. Per unit of area, graininess is the same, but an increase in surface area buys you more latitude, practically speaking.

 

So, by how much would you have to overexpose the 2-perf frame to show the same subjective graininess as the 4-perf frame? Is there some kind of rule-of-thumb that you can apply between different frame sizes?


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#2 David Mullen ASC

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Posted 09 February 2018 - 10:02 PM

I assume you are comparing 2-perf full aperture 2.66 : 1 to 4-perf S35 2X anamorphic, which also would be 2.66 : 1.

 

Trouble is that they share the same horizontal dimensions, only the vertical is twice as big so I guess unsqueezed, the anamorphic image would have "fat" grain, stretched horizontally since it was round on the negative but that had an image with a 2X squeeze.

 

The anamorphic printed image would be enlarged less to fill the same sized screen as a 2-perf print, so would look less grainy.  I don't think you'd see a difference in dynamic range.  

 

Overexposing doesn't reduce grain size, it just exposes the smaller, slower grains in between the larger, faster grains so that they become developable, creating a "tighter" grain structure.  Also, in terms of contact printing, a denser negative would have deeper blacks, better contrast.

 

So all you can do to match graininess is a combination of using slower stocks when possible and overexposing a little on the smaller format... but it is not technically an exact match because the grain shape would be different with anamorphic lenses.  But in theory it would be better to use the next slower speed stock which would have physically smaller grains in it as opposed to overexposing the same speed stock.


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#3 Karim D. Ghantous

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Posted 10 February 2018 - 06:59 AM

David, thanks. I do understand and agree with all of that. The reason I asked is purely technical - I think film has a wonderful alchemy to it, and the more I understand it, the happier I will be.

 

I agree that you would naturally use a finer grained stock for the smaller format. But what if you have access to only one stock? What if the stock you are using has only one variant?

 

And there are other issues, too. You're not just losing highlight detail - you're losing sharpness once you overexpose too much. This is no bad thing per se. But it helps to know what effects you're getting and when they kick in.

 

Some photographers who shoot portraits or weddings sometimes use this technique, as you may be aware. For example, one photographer I know of shoots Portra 160 at ISO 40 and develops normally. From what I have seen, it works very well. The whole point is to reduce sharpness using the properties of the emulsion. I would not be surprised if a few DPs have also used this technique.


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#4 David Mullen ASC

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Posted 10 February 2018 - 11:30 AM

You'd have to overexpose negative quite a bit to lose sharpness -- the typical 2/3-stop overexposure that many DP's do actually has the opposite effect when printing the negative, the slightly denser negative printed at higher lights has deeper blacks in the print, which gives the impression of better contrast and thus better sharpness.
 
Extreme overexposure, like 2-stops or higher, puts detail into the flatter shoulder of the characteristic curve so midtones look a bit flatter and milkier and thus softer.  You see this in some of Conrad Hall's work like in the day exteriors of "Tequila Sunrise".  Vilmos Zsigmond went even further for a day exterior beach party scene in "The Long Goodbye", overexposing plus heavily flashing the negative (plus I think using Double Fog filters).
 
Overexposure plus pull-processing, which lowers contrast, also acts to soften the image.  Roger Deakins overexposed the desert flashback in "Courage Under Fire" by three stops and pull-processed by 2-stops to compensate, giving that sequence a muted quality.
 
French cinematographer Yves Angelo used to do a more subtle thing, which was mildly overexpose and pull-process the stock for close-ups as a form of diffusion.
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#5 Matt Figler

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Posted 12 February 2018 - 11:42 AM

This is an interesting question, I've often wondered if there are any films that have shot both -- 2 perf for dialogue scenes in order to get longer takes/economics and 4 perf anamorphic for MOS, beauty or b-roll etc. Any references for this?

 

I suppose it would cost a good bit more to have multiple camera bodies and lens sets v.s film/develpment cost savings but none the less I would be interested to see. I also wonder if it would be easier to degrade your 4 perf anamorphic negative (via push process) to match 2 perf than to overexpose/shoot tighter stocks to 'upgrade' your 2 perf negative?


Edited by Matt Figler, 12 February 2018 - 11:44 AM.

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#6 David Mullen ASC

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Posted 12 February 2018 - 12:22 PM

I can't think of anything like that, 2-perf for long takes, 4-perf anamorphic for beauty shots, wide shots, etc.

 

"Titanic" did shoot 2-perf for longer takes underwater when they photographed the actual wreck under the Atlantic, then the movie itself was 4-perf Super-35.

 

"City of God" and "The Constant Gardener" shot Super-16 for the bulk of the movie but 35mm for the wide shots.

 

As you say, it is often not possible to carry two completely different camera packages and different type of lenses for a typical smaller production.

 

There have been some movies that mix anamorphic and spherical though, especially in digital.


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#7 Chris Burke

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Posted 12 February 2018 - 06:27 PM

This is an interesting question, I've often wondered if there are any films that have shot both -- 2 perf for dialogue scenes in order to get longer takes/economics and 4 perf anamorphic for MOS, beauty or b-roll etc. Any references for this?

 

I suppose it would cost a good bit more to have multiple camera bodies and lens sets v.s film/develpment cost savings but none the less I would be interested to see. I also wonder if it would be easier to degrade your 4 perf anamorphic negative (via push process) to match 2 perf than to overexpose/shoot tighter stocks to 'upgrade' your 2 perf negative?

Harmony Korine's Spring Breakers used 2 perf and anamorphic. For which reason??????

2 perf can look really good.


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#8 Matt Figler

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Posted 12 February 2018 - 07:28 PM

Harmony Korine's Spring Breakers used 2 perf and anamorphic. For which reason??????

2 perf can look really good.

Good call, need to rewatch that one


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