Resolution of Film

This was touched on briefly in another thread but I didn't pursue it to avoid dragging the thread off-topic (though it's never stopped me before and probably won't again ).

I spotted this on Wiki (yes I know) with regards to the film Spartacus:



While 4k/UHD is now available through the likes of SkyQ, it begs the question: Theoretically there should come a point where there is no need to "bounce down" films to 4k or 1080p or even as far as regular DVD - where does that point occur on (I presume) 35mm film?

I can't work out what you mean by that. What do you mean by there being "no need"?

Can't work out what you mean by "how high is it" in the title, either!

I'm not sure what the question is either.

The question I was expecting was "at what resolution does it become pointless, on 35mm film, to increase the scanning resolution any more, as doing so would reveal no more detail?"

Okay let's have another go (I've taken the description out in the title)

Let's take the original example, Spartacus. It is my understanding that to convert this film into a format that I can put in my DVD player at home it has to be bumped down to a format that fits on the disk and negates the quality of the picture. I'm assuming 35mm film is better picture quality on the original negatives than it would be on my DVD player.

My question should really have been pretty much what Bilky Asko said: With the advance of 4k, 8k and whatever else in the future, does there come a point where I could buy Spartacus in a picture/media format close to the picture quality of the original 35mm negative or are we already past that point with 8k and 4k? ie can it be scanned to, for argument's sake, 16k or even 32k? Or does that level of detail not exist on film?

While there's nothing to say it's impossible, anything past 8K would be useless on a consumer basis unless we had colossal televisions. Even today, you need a screen of significant size to truly get the benefit of 4K. These films were made to accommodate huge screens in cinemas, sizes of which I can't see people being able to fit into their houses. I've heard and read people say that you'd need a screen around the 100" mark to actually appreciate 8K, otherwise you can't fit all the pixels on the screen and you won't be getting the proper resolution.

I, for want of a better term, "lost my s**t" when we went HD in our house. But while the demos in shops look great, I've yet to be blown away by any 4K content. Granted all I've seen so far is Netflix stuff and my internet connection could be affecting the bitrate, but I'm finding myself paying far too much attention to trying to spot any extra clarity.

Sort of.

The original 35mm film will have been scanned. In days gone by this would have been telecined to SD "PAL" or 16:9 - with around 720x576 resolution.

If the film was scanned at HD (1920x1080), UHD (3840x2160) or 4K (4096x2160) and the SD version produced from this, then the SD will have been down-scaled, down-sampled, down-converted, down-resed - whatever you want to call it. This may look a lot nicer in SD than a native SD telecine transfer, even though the final resolution is the same. (Obviously if you aren't using 16:9 aspect ratio the resolution will drop in one dimension or the other as these are 16:9 resolutions)

However as part of most remastering processes, you benefit from more than just higher resolution scanning, and get better colour rendition, cleaned up dirt/scratch/sparkle etc. and these remastering processes will still benefit from these improvements, and there is a also a factor in downconversion called 'oversampling' which means the SD result from a downconvert can be noticably cleaner and sharper with information all the way up to the maximum SD resolution (out performing that of an SD telecine done in the SD domain)



Yes - even a decent 35mm film print will out perform SD DVD in resolution terms. Super 16 and 16mm decently handled will massively out perform SD DVD too.



Yes - there is a limiting point. It will, to a degree, depend on the original quality of the film stock used and the size of the film frame that was used (there are different ways of shooting 35mm that use different film areas - the larger the area, the higher the resolution of the image captured on a given film stock)

The other thing to be aware of is that since the 90s, Digital Intermediate post production has been used for movies, where the camera negative is scanned, the film edited in the digital domain, and the final master then written back to film. A lot of this has been done in the 2K domain, so unless you go back to the original negatives, match edit (and re-grade, re-composite and re-render effects shots etc.) you may not do much better than HD for some more recent films.

Older movies that were cut in the film domain may fair better (and may not require you to go all the way back to negatives to get a good result)...

AIUI good 35mm negatives shot with high quality lenses have >4K resolution, but below 8k. However once you go through the film production process in the optical domain it can drop below 4K.

Lots of digital cinemas are still 2K too...

The streaming stuff is dreadful. Even at the highest bitrate, Netflix is still very heavily compressed. The DVB-T2 HEVC tests done for the 2014 World Cup were at around 35Mbs 2160/59.94p and looked pretty nice (even though the HEVC compression was quite new). Compared to Netflix, which runs at around 15Mbs for UHD, this is a LOT higher bitrate - and looked a lot better.

The HDR UHD stuff I've seen recently has been cracking - though this has been at production bitrates (400Mbs+), and I've seen uncompressed (or very lightly compressed) 10bit 4:2:2 UHD broadcast camera outputs that were >8Gbs... They looked VERY nice.

That depends how far you sit from it.

It comes down to angular resolution in the end, rather than the size of the screen.

THIS ^.

Incidentally for a long time broadcast R&D and TV manufacturers assumed a certain picture-height to viewing distance ratio - and assumed that people sat at it. However as people moved from 28" CRTs to 42" Plasmas to 55" LCDs, it became clear that many people were sitting in the same place, with the TV in the same place, so the fixed picture-height to viewing distance ratio was a non-starter. People were viewing from a fixed distance irrespective of the picture height (i.e. screen size) in many cases.

A US engineer realised this years earlier (as CRT screen sizes increased) and this distance is named after him, the Lechner distance : http://www.schubincafe.com/2014/04/28/he-went-the-distance/