Article: Is 6K overkill? Lowry and Harris differ

[Grubert]

Sound & Vision Magazine

Excerpts:

[...]

Warner Brothers recently announced they're transferring A Star Is Born to digital video at 6K resolution, and will release it on Blu-ray Disc and DVD — though, of course, at those formats' maximum resolutions, 1080p and 480i, respectively. We just gotta ask: Why?

[...]

“The higher the resolution, the higher the through-put, the more onerous to move data," notes The Film Preserve's Robert Harris — who has worked on many modern restorations, including The Godfather, Lawrence of Arabia, and My Fair Lady. Harris says 6K is unwieldy to manipulate in post-production. "Moving data in 4K is horrific. It’s four times as much data as 2K." Consequently, Harris speculates that the 6K scan will be down-converted to 4K.

So is it worth it?

“A 6K transfer is just an attempt at marketing position," declares Lowry Digital Images' Chief Technical Officer John Lowry, who's done high-definition and 4K transfers on some of Hollywood's greatest films, including North by Northwest, Gone with the Wind, Citizen Kane, Snow White and the Seven Dwarfs, Singin' in the Rain, and the Indiana Jones and Star Wars collections. "Everything on film is captured at 4K, down to the film grain. In fact, if there is any motion, there’s even less resolution than 4K. If the camera pans, there’s less than 4K. The bottom line is this measurement of resolution is fragile. Any movement, and you’re probably at 2 or 3K in terms of actual resolution due to the blurring caused by camera shutter limitations (similar to how movement causes a blurry image when you’re shooting a still frame picture). Even slight camera pans and tilts will cause this. If you’re gonna talk about 6K, why not 8K, or 10K? At some point, it just becomes ridiculous. Bottom line: 4K is pretty darn good.”

[...]

Lowry also feels the lenses used to shoot A Star is Born will limit the effectiveness of a 6K transfer. A Star is Born was shot in CinemaScope [...].

According to Lowry, the only benefit of a 6K transfer over 4K might be some slight bit of detail in the noise floor: 4K resolution is already getting lost in the film grain. It's Lowry's position that instead of higher resolution, we should clamor for higher dynamic range. “Instead of 10 bit, why not 16 bit?," he asks. "Wouldn’t it be nice to have high dynamic range?” This will reveal more details in the shadows and the blacks, with higher frame rates for film. The advantages of 6K, if there are any, are so subtle that the economics outweigh the benefits. Perhaps it would be more beneficial to save the money spent on such a costly transfer — a 6K scan requires a new telecine scanner, such as the Northlight CCD — and instead direct Hollywood budgets to save more historic movies at 4K.

Harris, meanwhile, actually has used the Northlight 6K scanner — on the subtitles in Godfather II. “I like the image to be as perfect and as true to the original film as possible," he says. "So rather than digitally creating new subtitles, we went back to the original title rolls, and we scanned them in 6K and down-res’d to 4K. This gave us a slight advantage — a knife edge image. Everything else we did at 4K.”

Warner Bros. hasn’t responded to requests for interviews, so we cannot say why they’ve chosen this movie for the 6K treatment, or if they’re going to down-res to 4K. But Harris is coming down on their side.

“A Star is Born is an important film to do — it’s one of the great films," he says. "The performances are extraordinary, and it’s something that needs to be preserved. Is there an advantage to scanning at 6K? Slightly. Is it a good idea? I think it’s a great idea. There is nothing in A Star is Born that’s going to be above 4K. There just isn’t any 4K information in there. But you make sure you get every last drop you can. And that is the Warner ethic. Do I think they’re doing it correctly? Absolutely. Would I do it that way? Yup!”

Lowry's not buying it. “If you recover absolutely everything on the film, no matter what the display technology is in 100 years, you've already captured everything,” he insists.

[Neil_Luv's_BLU]

Originally Posted by Grubert

Sound & Vision Magazine

Excerpts:

The higher the resolution the better I say. 4K is excellent. But look at the 8K visual fx in Blade Runner... Just stunning. My Jaw actually dropped first time I saw BR on Blu-ray.

[Grubert]

Originally Posted by Neil_Luv's_BLU

The higher the resolution the better I say. 4K is excellent. But look at the 8K visual fx in Blade Runner... Just stunning. My Jaw actually dropped first time I saw BR on Blu-ray.

True, but the effects shots in Blade Runner were shot on 70mm stock, so there was more resolution to preserve.

[Bobby Henderson]

6K isn't overkill. Arri makes a very good case for 6K-based 35m film scans when doing 4K digital intermediate work (this is in an article they published which is carried on the E-Film web site). Spatial detail is better resolved and problems with moire and frequency sweep problems involving pattern detail are better fought when the original image was acquired at 6K level. The same paper also states that any 2K digital intermediate work should come from a 4K level scan.

[Josh]

My favorite quote:

The bottom line is this measurement of resolution is fragile. Any movement, and you’re probably at 2 or 3K in terms of actual resolution due to the blurring caused by camera shutter limitations (similar to how movement causes a blurry image when you’re shooting a still frame picture). Even slight camera pans and tilts will cause this.

But wait, Blu-ray is nearly 2K (and Panasonic has shown me that you can't tell the difference), so we are pretty much there for action films!

[Shadowself]

Lowry's not buying it. “If you recover absolutely everything on the film, no matter what the display technology is in 100 years, you've already captured everything,” he insists.

To Lowry and others who claim 4K captures every bit of spatial detail, I'd say...
Scan several minutes of film (say 30 minutes or more) that has a fair to high amount of motion and changing backgrounds at both 6K and 4K. Then compress both of them with the best lossless compression technique you can find. [Use one of the multipass techniques that uses 4+ passes if you can get your hands on it.] If the resulting file sizes are significantly different, say more than 5% different, then you are most definitely *NOT* capturing everything at 4K.

I'd almost guarantee this to be true for most films. There is more information in the 6K (or 8K) scan than in the 4K (or 6K) scan for most films.

Just because the file sizes are large does not excuse the archivists from doing the job right. Complaining about large file sizes when creating a true archive is just whining! For LOA, for example, at least the archivist is in a nice lab/office not out in the middle of the desert shooting the film! Especially for such classics, creating "archives" using anything short of the best technology available is, IMHO, tantamount to a crime. [20+ years ago the teams I worked with complained about GBytes per event then that became a trivial size even fitting on one hard drive, then 10+ years ago they complained about TBytes per event now that fits on one or two hard drives on the desktop, now they're complaining about 10s of TBytes per day per event, in less than 10 years that will be considered trivial ... so whining about file sizes being difficult to deal with is just that -- whining]

The problem with creating an "archive" is that 10, 20 or more years from now people will believe the "archive" is synonymous with the original camera negative. Thus the question becomes, "When we can easily store the digital archive why continue the special efforts needed to preserve the OCN?" When that question gets asked and the budget conscious studio executive looks at the bottom line dollars, the OCN gets lost in the shuffle.

On the other topic brought up, I agree that bit depth should be increased. I doubt that 16 bit is necessary in all cases, but it may be useful for some films that have very high contrast. But, the bigger issue for me are the organizations that are still using Bayer arrays to capture imagery. For your home "point and shoot" cameras, Bayer arrays are fine. However for professional work they should be banned. Multiple, co-collimated focal plane arrays (one per color of interest) is the only way to go. For most purposes I'd rather have 12 bits with 3 or more independent FPAs than a 16 bit Bayer array.

[AliceT]

Its never overkill. Someday, 6k will be standard, and if you are going to remaster something, might as well do it as high as possible, so you dont have to go do it again years from now.

[space2001]

I am a compositor for film and have work in different formats, 2k, 4k imax.

you can barely tell the difference between 2k and 4k, 6k is overkill and is not needed. no one will notice the difference between 4k and 6k.

now imax is a different story. it 70mm and can be scanned at very high resolutions and you will see the detail of that.

[Shadowself]

In fact, if there is any motion, there’s even less resolution than 4K. If the camera pans, there’s less than 4K. The bottom line is this measurement of resolution is fragile. Any movement, and you’re probably at 2 or 3K in terms of actual resolution due to the blurring caused by camera shutter limitations (similar to how movement causes a blurry image when you’re shooting a still frame picture). Even slight camera pans and tilts will cause this.

This would imply to me that he does not realize that proper registration of that blur is important.

This is one of the reasons that older special effects on film did not look as real as live action -- no blur or inaccurate "faking" of the blur. IIRC Young Sherlock Holmes (by Spielberg) was one of the first, if not the first, to attempt to get the blurring correct for special effects. Since then additional refinements have helped lead to more and more realistic effects.

Accurately capturing blur is important. It is additional information our eyes and brains use to convince us the motion imagery on screen is actually moving and not a series of still images.

So, at least the way I view it, to say that motion in the field of view is an excuse to use lower resolution scans is not any different from the camera being still and virtually everything in the field of view moving -- crowd scenes, or stampeding animal herds, anyone? Because there's so much blurred imagery in such scenes should we just do 2K scanning?

Also if Lowry's worried about resolution loss due to shutter movement... is he radically against the rolling shutter focal plane arrays used in many cameras? Or has he not even thought of that?

[Deciazulado]

We are talking archiving for the future here.

For exhibition 2000 x 4000 is probably enough for most sitting distances.

[WickyWoo]

I would agree with Deci, when creating the archival master, the bigger the better. Exhibition on the other hand not as important

[Shadowself]

Originally Posted by space2001

I am a compositor for film and have work in different formats, 2k, 4k imax.

you can barely tell the difference between 2k and 4k, 6k is overkill and is not needed. no one will notice the difference between 4k and 6k.

now imax is a different story. it 70mm and can be scanned at very high resolutions and you will see the detail of that.

Have you ever *seen* an "8K" projection in person? There are systems out there, admittedly very, very few, that actually do "8K" (well, technically 4096 x 8192). Once you've seen those with real, 8K (or down sampled 9K or 11K) imagery then compare that with 4K I believe you'd easily see the difference.

From my experience, 6K is not overkill in many circumstances. It's not even close to overkill.

Originally Posted by Deciazulado

We are talking archiving for the future here.

For exhibition 2000 x 4000 is probably enough for most sitting distances.

I agree. For most situations 4K (2160 x 4096) is enough.

But if someone does another Ben Hur type movie would approximately 1480 x 4096 be enough? Or would you want at least 6k (lower case) horizontal resolution to get approximately 4K (upper case) vertical resolution?

[JadedRaverLA]

Originally Posted by WickyWoo

I would agree with Deci, when creating the archival master, the bigger the better. Exhibition on the other hand not as important

I'm not so sure that this isn't a bit of an artificial disagreement. Every time I've seen 4k+ scanning discussed with Robert Harris the issue has primarily been archiving the master in the highest possible quality.

The article was talking about Blu-ray and DVD, and Lowry's (DTS's) objections seemed to be more based on that. It really seems like they got two different opinions on two unrelated things.

I gotta agree with Robert Harris, though, for archiving purposes. Scan at the highest res you can get away with. You can downrez to 4k to prevent the data rate from ballooning out of control. But capturing at highest res possible with the scanner should provide a slight PQ boost to the resulting 4k image... especially during fast motion.

I also agree that it probably won't make a bit of difference to Blu-ray (at basically 2k.) Scanning at 4k is useful in that you have additional resolution for when motion knocks the resolution down a bit, and for properly resolving grain. But going from 4k to 6k (on 35mm or Super35), probably won't make a bit of difference on homje video.

Just my $.02

[dialog_gvf]

Originally Posted by Deciazulado

We are talking archiving for the future here.

For exhibition 2000 x 4000 is probably enough for most sitting distances.

Actually, I see a combination. The ARCHIVAL should be attempting to capture, to the limits of current capability, the maximum resolution AND dynamic range possible.

And if dynamic range is important for presentation, then it's important to be in the archival too.

As people have argued concerning home video, we are now at the point where 2K (HD) presentation is sufficient for the vast majority of likely presentations, so increasing the colour resolution beyond QHD (going to 4:4:4 from 4:2:0) and the colour depth to deep colour (12-bit v. 8-bit) and introducing constant height encodings are all bigger wins than simply boosting the luminance resolution.

Gary