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This topic comprises 2 pages: 1 2
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Topic: New "Theatres Going Digital" article
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Evans A Criswell
Phenomenal Film Handler
Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000
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posted 12-30-2003 10:05 AM
quote:
Yes, the recommended brightness is 12fl for digital, but that is because it is measured differently. For film, we measure it open gate, with no film (16fl target). With transparent film stock, it should be about 12fl. And of course, von Sychowski is giving you his opinion, indirectly through Reuters' quotation.
Good points about the brightness measurements and the "quotations through the press" (I've experienced my own statements being distorted to a degree that way myself).
We've had film vs. digital threads before, but I've never had a satisfactory answer to the question of, from an information theory standpoint, what digital resultion, using a rectangular lattice, is required to have the same information present as film. This is really two different question with two different answers:
1. What digital resolution and pixel color depth are required to capture the information from a scanned film source (say full aperture 35mm scope filmed anamorphically, to maximize resolution)?
2. What digital resolution and pixel color depth are required (assuming digital source and projection) to portray the same information as is present in, say, an anamorphic 35mm film source (full aperture scope)?
I believe #1 will require a higher resolution than #2. And by "portraying the same informaton", I dont mean "looks the same to a human viewer from a certain distance" -- I mean "has the same inherent amount of information". I know the answers vary depending on film stock being used. People have mentioned thatscanned film sources do not look nearly as good projected digitally as movies generated totally from a digital source.
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Martin Brooks
Jedi Master Film Handler
Posts: 900
From: Forest Hills, NY, USA
Registered: May 2002
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posted 12-30-2003 02:21 PM
As with any technology, you gain something and you lose something with digital presentation. As I've written before, I have been extremely surprised at how good the digital presentations I've seen have been. And I was inclined (and still am) to hate it.
With digital, you lose print grain and you gain steadiness. This really does make a big difference. I walked out of a digital presentation on one screen and into a 35mm presentation on another screen (of the same film) in the same theater and the 35mm seemed so murky in comparison, at first I thought there was something wrong with the 35mm, until I got used to all that grain again.
However, with digital, you lose color dynamics, especially deep blacks. And although I haven't noticed it so far, I'm sure there will be movement and other artifacts. I haven't noticed any pixilation, which other posters in other threads have claimed were obvious.
So one issue is that for the average film-goer, which will look better? I hate to admit this, but I think that digital will be perceived to be better, if presented properly.
One strange thing I've experienced when comparing 35mm screens to digital screenings is that the sound seemed inferior on the digital presentations. I don't quite understand the reasons for this - aren't the bit rates on the digital presentations at least as good as 35mm SR-D, DTS or SDDS?
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John Hawkinson
Film God
Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002
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posted 12-31-2003 12:39 PM
Evans asks some questions about number of film grains, and levels, etc.
This is a very complicated topic, and I bet John Pytlak will do a much better job of trying to distill it than I can (I sort of regret even trying...). Kodak has some extremely in-depth documentation on this topic (see below), but it's kind of hard to assimilate and distill into direct answers to your questions.
First of all, the grain size is not constant, it ranges from 2e-3 mm to 2e-4 mm. There are different grain densities within each color layer. The apparent grain resolution is a function of contrast and exposure and lighting, and what you see on the release print is a combination of all these factors from the camera negative to the interpositive to the internegative to the release print.
For each of their film stocks, Kodak publishes a "Modulation - Transfer Curve" and a "Diffuse RMS Granularity" curve. You can find them in the spec sheets for the different film stocks. i.e.:
http://www.kodak.com/US/en/motion/products/negative/ for negative films.
http://www.kodak.com/US/en/motion/products/postProducts.shtml for intermediate and release print films.
What do these curves mean? Well, this is documented in some detail in the mammoth Kodak publication Kodak Motion Picture Film: H-1.
Specifically, two subsections seem to be most relevent, both under "Selecting Your Films."
Exposure Information, specifically "Image Structure," "Understanding Graininess and Granularity," and the subsequent sections.
Also, Sensitometric and Image-Structure Data.
I'm not sure that resolution is a meaningful concept when you're talking about different sizes of dots (grains), so I don't know how you come up with a good answer to the question you phrased. Obviously there has to be some effective resolution that a film scanner should shoot for, but I don't know if it needs to be far higher than the average number of grains per unit distance/area. I guess this has to be known territory for comparing halftones with straight 1-bit-depth bitmaps, so there are probably some industry-standard approximations.
--jhawk
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 12-31-2003 01:20 PM
Sorry, even though they are Kodak papers, the copyright is held by the SMPTE, so you either have to find the SMPTE Journals in a library, or become a member.
Student membership in the SMPTE is very worthwhile, and not that expensive (only $35 per year):
http://www.smpte.org/membership/individual/join_now/
If you read the papers cited, you will see that the upper limit on required resolution is a function of how many digital artifacts you can tolerate. Scanning and recording at 4K can look really good, but some will still be bothered by the visibility of the artifacts. And obviously, 2K is successful in today's movies (but 2K movies are often below my quality expectations, as well as the expectations of many cinematographers).
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Steve Kraus
Film God
Posts: 4094
From: Chicago, IL, USA
Registered: May 2000
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posted 12-31-2003 03:24 PM
Comparing pixel counts to film rez is a bit apples & orangish since film rez goes on and on but at diminishing constrast levels til it disappears into murk (the interested should read up on modulation transfer function) while digital imaging schemes, like digital audio, is hard limited so it's difficult to draw a direct comparison. That disclaimer aside if it's said that 4K or more is required to capture what is on a 35mm negative then what is necessary to reproduce what is on a print? The print, especially one made from a dupe negative, will have much less rez than the negative. 1.1K projection isn't quite up to snuff. How do the 2K systems look?
Why, when the subject of satellite distribution is brought up, does someone trot out the same old nonsense about signal disruption? Give it a rest, already! Live feeds might be involved in sporting events etc. but I've never heard anyone advocate it for movies. Obviously the data would be sent in advance and cached on a drive array at the theatre. Packet switching & reassembly, error detection and correction, retransmission when needed, etc. would ensure delivery of complete files. I'm not an advocate of digital cinema but this business about planes flying overhead blocking the signal is a non-issue. Yes, the signal could be disrrupted but it would have no effect on cinema performance except to make the download, the day or night before, take longer.
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Scott Jentsch
Phenomenal Film Handler
Posts: 1061
From: New Berlin, WI, USA
Registered: Apr 2003
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posted 01-05-2004 09:43 PM
Aaron Sisemore wrote:
quote:
Scott, there is a vast difference between digital origination and digital projection. Usually (but not always) the resolution of the originating hardware is far higher (but not as high as film) than any of the DLP projection stuff currently out there. 'D-Cinema' as the article and many of us are arguing about is specifically referring to the projection aspect of the medium.
Yes, I understand the difference betwen digital origination and digital projection.
My point was that the films I mentioned were originated digitally, and therefore would have no greater resolution on film than they would if projected digitally. I apologize for not making that more clear, I should probably have put something in italics to emphasize that I was making a play on the words to make my point.
This would, of course, only be accurate if the cameras were the same resolution as the d-cinema projectors, but I assumed that they were both the same.
There is no way to "create" resolution, so if the cameras were 2k, then the movie was a max resolution of 2k no matter if it was on film or on d-cinema.
If the film was created at a higher resolution than the source, then interpolation or some other method of increasing the resolution came into play. That usually creates a soft picture unless sharpening and edge enhancement are applied, which degrades the image if applied too liberally.
So, whether you have a digital projector or not, most theaters showed a couple of digital movies in 2003. If I recall, they did quite well.
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