HD to 35 transfer

[Guest Peter Waal]

Sorry if this has been dealt with elsewhere, but I can't find it.

 

Is it true that a 2K DI of 35 mm footage results in only 777 lines of vertical resolution?

 

If this is true, then:

 

a. Does this account for the generally underwhelming prints I've been seeing in theaters lately? I've had my eyes checked (seriously) and they're fine.

 

b. What EXACT process should I use to transfer HD 1080/24p to 35 mm for the best possible results?

 

If my initial info regarding 777 vertical lines in a 2K DI is wrong or otherwise misguided, please correct me, and back up what you say. I'm simply trying to cut through the technobabble and get to the bottom line.

[John Pytlak RIP]

Since 2K is referring to the width of the image, the vertical resolution depends on the aspect ratio.

 

Almost everyone agrees that 2K scanning does not capture all the detail on a 35mm film negative. Published work by Kodak image scientist Dr. Roger Morton and his team show that even greater than 4K offers advantages.

[David Mullen ASC]

The actual recording to 35mm tends to be more standardized although companies tweak the LUT's (Look-Up Tables) as they see best. In other words, if you're worried about picture quality, the original photography and then the color-correction phase are much more important than the final recording to 35mm. If the final transfer is screwed-up and it's the transfer house's fault, you can get them to redo it, but they can't make up for bad photography and bad color-correction.

 

Most people will favor laser recorders like the Arrilaser transferring to an IN or IP as being sharper and cleaner, but some people prefer transfers to camera negative stock using CRT recorders because it adds some grain and softness that make the digital image look more film-like.

 

The key is to create a short (like two to four minutes) clip reel of various shots from the final color-corrected HD master and use that to test the film-out process.

 

Printing the final laser recorded IN onto Vision Premier or Fuji Hi-Con print stock is generally a good idea too.

[Guest Peter Waal]

Brilliant. That's exactly what I was looking for. Thank you.

[Michael Nash]

I'm not talking about scanning 35 mm camera negative. (I thought that was pretty obvious from my post heading: "HD to 35 mm transfer.")

 

But thanks for telling me 4K is better than 2K.

 

Duh.

<{POST_SNAPBACK}>

 

Well, you asked,"Is it true that a 2K DI of 35 mm footage results in only 777 lines of vertical resolution?" That's what John graciously answered.

 

In case there's any misunderstanding here, a 2K scan of film footage is NOT the same as HD originated material scanned to 35mm film (the resolutions are close, but not quite the same).

 

You complained about the "underwhelming prints" you've been seeing, and from your quetsions it's ambiguous whether you were talking about the quality of 2K DI's or the quality of HD transfers to 35mm film. I gather you were trying to compare the two, and John was offering his (rather informed) professional input. I don't see the need to be sarcastic, unless I've misinterpreted your post.

[Phil Rhodes]

Hi,

 

The Truelight colour management system is intended to take the guesswork out of this sort of thing - what you seen on the screen is, give or take out of gamut colours, guaranteed to be what you see on the print.

 

Phil

[Guest Peter Waal]

To be fair to John, he did give a partial answer in that he said aspect ratio determines vertical resolution, but he didn't specifically support or refute the specific question as to whether a 2K DI of 35 mm has only 777 lines of vertical res. Instead, he went off on a tangent about 4K scanning being better than 2K scanning, which sounded to me very much like a pitch for 35 mm neg, which I've heard a million times, and for which I blasted him.

 

I admit I was indeed too harsh. Apologies to John.

 

Now, I still don't know the answer to this part of the question. I believe the 777 figure was referring to 2.40 scope footage in a 2K film-out. Do you know if this figure is accurate or not? Any elaboration would be welcome.

 

Thank you.

[Dominic Case]

If you are simply talking about pixels or lines, then the maths is overwhelmingly simple. HD is 1920 x 1080 pixels. That's an aspect ratio of 16x9 or 1.77:1. If you want a 2.40:1 image, then you might get it by cropping top and bottom - that is, you reduce the vertical height by 1.77/2.40. That actually comes to 796 pixels height.

 

It the original was shot with an anamorphic lens, then you would be making better use of more lines of the HD image.

 

By the way, don't confuse HD originals with an HD scan of film, and don't confuse HD with 2K. They are all different things.

 

Also, don't confuse resolution (especially film resolution) with lines or pixels. Once again, not the same thing. Resolution involves a whole lot more things than a simple count of pixels.

[Guest Peter Waal]

Thank you.

[David Cox]

Peter,

 

I think you picked up the 777 number from one of my posts. This number was taken from a 2K image which although is 2048 wide, only 1828 were actively used, divided by the 2.35 aspect ratio. This is a real world example from a very major British feature film of some months ago, but is a standard resolution. Dominic is bang on with the rest of the math lesson!

 

I have this problem, the results of which tie in with Peter's concerns about soft prints! I spend a good part of my day looking at HD, 2K, 4K and upwards images. So when I go to the cinema, I see an image that is soft, grainy and dirty. Is it me ? am I too used to ?pure? images? Or are movies getting softer? When HD images were first shown, people thought they were too sharp. Question: are we getting used to the sharpness and actually are getting to the point where (dare I say it) we don?t like grain and softness any more? Its not an unprecedented thing. A telecine transfer of 10 years ago look amazing - 10 years ago. Now it looks as soft as the pope?s undercarriage! So is it possible that we are actually getting to like that sharpness??

 

Just to confuse people further, here?s a little brain-teaser about resolution and what it means to the image?

 

Imagine this - we want to shoot a white wall that is perfectly flatly lit. How many ?lines? do we need? Well, one actually. One big fat white line will perfectly describe the image we are trying to convey.

 

But as an alternative, lets now say we shot that white wall on film. Now how many lines do we need to describe the film as captured on that film stock? If we take into consideration film grain, any edge issues from the lenses etc etc, we might well now need a 4K+ image to capture all that info.

 

So, from this very crude and entirely impractical experiment, we could deduce that something captured digitally might have different demands on resolution to something captured on film. We might also deduce that we are increasing our demand on resolution for film capturing in order to accommodate film artefacts that actually were never part of the original scene. This argument applies even more to color depth. Having said that, it is probably fair to say that the 2K file size was a trade off between what was viewable and what was possible / practical, so there is room for improvement.

 

But back to Peters question #2. If you shot HD then you have 1080 lines of resolution at 1.77 aspect, unless you plan on cropping the image further. An Arri Laser is generally thought to be the best film recorder, although I have heard good things about LaserGraphics recorders?

 

David Cox

Baraka Post Production

www.baraka.co.uk

[Phil Rhodes]

Hi,

 

> We might also deduce that we are increasing our demand on resolution for film

> capturing in order to accommodate film artefacts that actually were never part of the

> original scene.

 

I bin' sayin' it, ain't I bin' sayin' it?

 

Shoot, post and project 2K is fine.

 

Shoot film, then post and project 2K looks like arse. Conclusion: 35mm prints are roughly 2K, depending on the process.

 

Phil

[Filip Plesha]

I don't want to put my nose where it does not belong,

but a 2K scope scan would have most resolution out of all current 35mm standards, since even thought it has 2.4:1 ratio, it uses 1556 lines of resolution

and 1828 pixels in each line (the rest is black unexposed area).

So that is the only exeption for the correlation between aspect ratio and number of scan lines, because it is squeesed

[Guest Peter Waal]

Thanks, David.

 

Just some observations:

 

I shot a film last year on HD (1080/24p) and transfered the master at Efilm to 35 mm. I reported in one of these threads that I felt the 35 mm print was barely acceptable. My film was well lit -- Efilm had no problem with any of our light or contrast levels. But the reason I say it was barely acceptable is because there were a lot of wide shots in the movie, and in those wide shots I found resolution became noticeably softer in the final 35 mm print. (The resolution seemed to hold much better on HDTV sets showing the HD master tape.) Closeups and medium shots were indistinguishable to film, IMO. But wide shots (all of which were in focus) looked a little too soft for my liking -- so soft that I'm gunshy about shooting my next project in HD. I regard HD as the poor man's 35 mm. I have no use for cheap HD cameras like Sony's HDV or the 720 offering from Panasonic. 1080 HD is on the borderline of acceptability for features, IMO.

 

So:

 

If anybody has some advice about how to ensure resolution holds in wide shots in HD, I'm all ears, because my next project is going to be full of them.

 

Re: Phil's statement that shooting film and posting 2K delivers a print that "looks like arse."

 

I tend to agree, but I'm not sure it's only the process that should be blamed. I've seen a lot of really weak prints lately. So weak that I actually went to get my eyes checked (they're fine). I've seen some stuff at the Arc Light in Hollywood that looked great, but pretty much everywhere else I go the prints seem to look lousy. I'm beginning to suspect lousy projectors and lamps are the main culprit here. But I don't have enough background to know where this is a likely situation or not.

 

I've heard so many DPs, guys I really respect like Deakins and Seale, claim that they love what 2K offers them. They seem to love the print quality they get and are in no hurry to go back to optical prints. But I'm wondering if they feel that way because they screen their prints at Efilm, which has the best gear, in top working condition. The rest of us may just be watching 2K prints on crappy machines.

 

Your thoughts....

[Tenolian Bell]

Shoot, post and project 2K is fine.

 

Shoot film, then post and project 2K looks like arse. Conclusion: 35mm prints are roughly 2K, depending on the process.

 

Phil

<{POST_SNAPBACK}>

 

I don't quite understand.

 

What is the point?

[David Mullen ASC]

HD resolution IS barely acceptable for wide shots when projecting the image on a large screen. The same for all-2K D.I.'s of 35mm-shot movies (4K scans downrezzed to 2K are a little better, detail-wise.) When shooting 1080P HD you are just running into the resolution limits of the camera and recording format.

 

That doesn't mean you can't make a good-looking movie in HD with reasonable sharpness and detail -- there are plenty of 35mm movies posted traditionally (contact or optical) that don't have particularly sharp wide shots either. I mean, look at "Titanic", which was blown-up from Super-35 optically, not digitally -- it's a little soft in the wide shots. Look how many people though "Sideways" looked too soft. Some 35mm movies use softer film stocks and softer lenses and diffusion and don't particularly have sharp wide shots, so certainly you can make an HD film seem acceptably sharp even if it isn't as sharp as 35mm CAN potentially be.

[Max Jacoby]

Printing the final laser recorded IN onto Vision Premier or Fuji Hi-Con print stock is generally a good idea too.

 

The Agfa print stok is a very good option too. I didn't know it even existed until last year, but then I saw a test for a film that I did and it was flat out better than the Fuji High Con, with better blacks and more shadow detail.

[Phil Rhodes]

Hi,

 

> What is the point?

 

That the demands being made of the DI process are being increased by the requirement for it to recreate the artifacts of film.

 

I present this merely as an observation... it's not a criticism of anyone.

 

In practice what this means is that while it's probably quite correct to push for 4K DI for film originated material, we now also seem to be chasing 4K for digital acquisition, which given this reasoning is probably not necessary to equal the perceived resolution of current 35mm optical post.

 

However there's nothing wrong with that - shoot, post and project 4K and I'm sure it'll look very nice indeed.

 

Phil

[David Cox]

Oops - sleeping while the debate is raging, so playing catchup. Damn timezones!

 

but a 2K scope scan would have most resolution out of all current 35mm standards, since even thought it has 2.4:1 ratio, it uses 1556 lines of resolution

<{POST_SNAPBACK}>

 

yes this is quite correct and the best way of making the most of 2K for widescreen presentations. However, it is surprisingly rare to see an anamorphic (full height) frame even from films that would not appear to have budgetary restrictions. There seems to be a big leaning towards shooting a "flat" frame, which of course limits both film and digital resolutions. Why is this?

 

But the reason I say it was barely acceptable is because there were a lot of wide shots in the movie, and in those wide shots I found resolution became noticeably softer in the final 35 mm print. (The resolution seemed to hold much better on HDTV sets showing the HD master tape.)

<{POST_SNAPBACK}>

 

Yes, this is where the resolution issues are most noticeable, although I am interested in your point that you felt the HD master tapes were better. I assume you were looking at them close enough so that the image filled as much area on your retina as sitting further away from a bigger screen (if you see what I mean)? If so, this is a reasonable comparison for the purpose of assessing detail level, and this suggests that the failure is actually somewhere between the film recording and the final print. Have you raised this with the operator of the film recorder? These devices can use interpolation in order to rescale the HD image to "film size" and I wonder if there is a problem here? Otherwise, perhaps that extra generation of film is the culprit - just that little extra grain and softness? Film grain is a major detractor from detail. From our post production point of view, film grain is one of the biggest issues when we use motion tracking - which is where the computers are trying to follow detail to get an accurate motion trace. When you look at a part of an image this closely, you can see how destructive the grain is to the detail.

 

I wonder if you went back to your HD tapes and had a viewing with a decent digital projector on a large screen, whether this would look better or not. 50/50, possibly!

[Phil Rhodes]

Hi,

 

> There seems to be a big leaning towards shooting a "flat" frame, which of

> course limits both film and digital resolutions.

 

Certainly limits film resolution, though some scanners (Northlight I know, perhaps other line-array types) are actually capable of scanning 2:1 pixels - that is, you can scan the scope area of a super35 frame into a 2048x2556-pixel image. Obviously, this is worth pursuing.

 

> Why is this?

 

Scope is a pain. The lenses don't match that well even when you get a "matched" set, if you're a big show shooting multiple cameras getting a lot of scope lenses is hard, they're huge, weigh a ton, have long minimum-focus distances, and they can be soft and prone to flare. They are expensive to rent and can make focus pulling difficult since the doubling of horizontal field of view encourages the use of longer focal lengths and they tend to be slow. Scope can make Steadicam and other specialist mounts more difficult due to the size and weight of the lenses, and other specialist cameras - such as high speed, aircraft-mounted or other special effects applications - may not be workable in scope. The DP might feel that certain scope artifacts are unsuitable for the storyline - the asymmetrical defocussing and horizontal flares are something I hate to see in period pieces, personally.

 

Although, as Mr. Mullen's recent stills from "Akeelah and the Bee" show, there are things they do that nothing else does.

 

Phil

[David Mullen ASC]

My experience with Agfa print stock -- printing trailers for "Northfork" -- showed it to be closer in look to the normal Fuji print stock 3510 or the old Kodak 5386, not Fuji Hi-Con 3513 D.I. or Kodak Vision Premier 2393. It's definitely not a contrasty print stock and the blacks seemed normal to me, not particularly deep. FotoKem uses it for various projects.

[David Mullen ASC]

In practice what this means is that while it's probably quite correct to push for 4K DI for film originated material, we now also seem to be chasing 4K for digital acquisition, which given this reasoning is probably not necessary to equal the perceived resolution of current 35mm optical post.

<{POST_SNAPBACK}>

 

We need 4K acquisition as long as we have 35mm prints, which will be for a long time. I might agree that all-2K would be fine if there were ONLY 2K digital projection out there, although even there most tests show that 4K-to-2K retains more fine-edged detail than all-2K.

 

Since 35mm print projection tends to be around 2K by the time it hits the screen, you need to have more resolution BEFORE it hits the screen, which is why all-2K posts look too soft when projected on large screens -- it's not enough resolution to survive the loss.

[Tenolian Bell]

HD resolution IS barely acceptable for wide shots when projecting the image on a large screen.  When shooting 1080P HD you are just running into the resolution limits of the camera and recording format. 

 

Look how many people though "Sideways" looked too soft.

<{POST_SNAPBACK}>

 

Just to add some context.

 

The softness of "SideWays" was a choice. I thought it was too soft at times also.

 

Which is different from from the softness inherent in the recording medium (compression/subsampling), that doesn't really record full 1080.

[Tenolian Bell]

Since 35mm print projection tends to be around 2K by the time it hits the screen, you need to have more resolution BEFORE it hits the screen, which is why all-2K posts look too soft when projected on large screens -- it's not enough resolution to survive the loss.

<{POST_SNAPBACK}>

 

A great example of this was Spiderman 2. I was astonished as to how sharp the image was and how well the live action and VFX matched.

 

I saw that difference even more when seeing I Robot which was a 2K show and how noticeably much softer that was. The VFX did not seem as real.

[Tenolian Bell]

In practice what this means is that while it's probably quite correct to push for 4K DI for film originated material, we now also seem to be chasing 4K for digital acquisition, which given this reasoning is probably not necessary to equal the perceived resolution of current 35mm optical post.

<{POST_SNAPBACK}>

 

I can agree with that. A 2K digital camera, 2K post, 2K projection would work fine. That would equal current 35mm projection.

 

But if we can accomplish 4K projection lets shoot for it. Movie theaters will probably need 4K projection soon.

 

If HDTV ever finally works out. If people can have large HD televisions or projections in their homes, the movie theater will need to offer something exponentially better.

[David Cox]

But if we can accomplish 4K projection lets shoot for it.  Movie theaters will probably need 4K projection soon.

<{POST_SNAPBACK}>

 

...of course the post budget will have to go up a bit. Doubling the resolution at least quadruples processing time and storage requirements. We're ready for it - its just a shame that producers increasingly look to post to cut budgets. And without 4K ability in post, the ideal stops there.

 

David Cox

Baraka Post Production

www.baraka.co.uk