IMAX - what does this mean in your system

[HDTV Forum]

The following is an exchange between Greg Hoey and I. Please enjoy.

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Greg,

I am perplexed.

Just watched Matrix Revolutions at a flat screen IMAX. What an accurate and immersive experience. It looked like a DVD and did not have the look of film I am used to at the local cineplex. The major difference being film grain with the IMAX having a very fine nearly imperceptible texture.

At the cineplex all films have grain. I watched Matrix Reloaded there and it was obviously grainy. In my display system there are two ways I can setup my black level where one has clean blacks and the other shows grain in the blacks. I have assumed the grainy blacks are the accurate presentation especially since this duplicates my experience at the cineplex with Matrix reloaded specifically. Based on the IMAX presentation that may not be the case. These were filmed altogether using the same camera and film techniques I assume. so...

Does the original negative have film grain? If so why doesn't the IMAX print?

If the original does not have film grain then the cineplex has it due to
sloppy prints?

DVD masters typically filter out grain to reduce bandwidth?

Confused without a reference,

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Hi Richard,

Nice to hear from you again.

FIREFLY comes out a week from Tuesday. YES!!!!!

Hey, good basic and therefore hard to answer questions.

I agree. I saw MATRIX TWO and THREE in IMAX and they blew me away altho I did think TWO looked a little better than three. I keep hearing rumors about the long cuts of LORD OF THE RINGS in IMAX . . . we should be so lucky.

Hmm, where to start?

YES, all film has grain. . . . just as different video displays have various and sundry sizes and shapes of pixels, different film stocks -- and there are MANY -- have different sizes and
shapes of grain IE the smallest component of the image. THE MATRIXS were shot in Super 35mm with the same cameras and lenses and film stocks that all other films use. . . and YES, grain is a desirable thing in film . . . . when the balance of all other factors is correct. Grain gives a subtle LIFE to the image . . more analog if you will.


There are several factors that make grain different from, say, fixed pixel arrays.

ONE -- the big one is that film grain MOVES and therefore draws more attention to itself. Keep in mind the simple concept that each frame of film has a slightly different arrangement of grain particles because of the way it is made.

TWO -- film grain is ADDITIVE. Grain increases when a film is printed because each additional generation of film copying adds another layer of grain. Keep in mind most prints we see in theaters are a COPY of a COPY of a COPY of the original film.

THREE -- mediocre film projection -- i.e. what we get in our crappy local multiplex [ REGAL ] still manages to show grain. SO we don't get the good stuff like fine detail and good
contrast but we still see the grain . . . which now looks worse.

IMHO good contrast and especially good peak white levels are what make film look like film as much as good blacks. It is easier to get a good black in film projection than a good white . . and when you get the good white the good black looks even better.

I think that proper screen brightness is the most obvious thing that made MATRIX IN IMAX look so great. The WHITES ARE WHITE -- they're not muddy grey. I saw MATRIX IMAX in a REGAL IMAX theater and then wandered into one of their big standard theaters and it looked flat and mushy and dim and grainy, just like films at Regal usually look. How come? Simple, Regal and many other chains simply run their projectors with bulbs that are too dim just to save money on electricity and of course they don't service the projectors and they're run by minimum wage high school kids. HOWEVER, the IMAX equipment is leased from IMADX, maintained by IMAX which enforces their quality standards and is operated by IMAX trained projectionists.

At the base level it really IS that simple. CONSCIENTIOUS QUALITY CONTROL.

Beyond that, the IMAX blow-up prints are digital so it's like getting a 65mm print directly from the ORIGINAL 35mm negatives without the problems of optical blow-ups. Optical blow-ups are controlled by some odd counter intuitive laws of physics. To get a REALLY big screen image the quality ends up being sharper with less PERCEIVED grain if the original film is enlarged to an
intermediate size ie 35mm to 65mm IMAX before it is enlarged to the BIG screen. I always thought it would be better to save the extra generation of film but it isn't.

Again, and sadly, films in theaters DID look better when I was a kid.

It's funny, Richard, to hear the film studios pushing DLP and DIGITAL CINEMA when it would be SO much quicker, cheaper and in many ways better to just follow the IMAX model of bright projectors and good prints. BUT since most of the audience can't tell the difference and doesn't complain those of us who CAN tell the difference are left crying in the wind . . . . as we retire to our home theatres.

I think the studios are pushing DIGITAL CINEMA for the same reasons the record companies are pushing SA-CD and DVD-AUDIO; They think it's easier to copy protect


Greg
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Greg,

Too cool on the Firefly - must purchase!

Thank you so much for your response explaining my experience. Alas the criticalquestion was not answered definitively and I prefer not to assume.

Based on your response it appears that what I am seeing at IMAX is reference. There was no film grain in the conventional sense. Therefore the DVD of this should also not have grain in the conventional sense. Correct?

Or, are they removing grain digitally to make the IMAX prints? Therefore a DVD that shows grain could be quite accurate? The IMAX prints are not reference, true to the source, since the grain has been removed?

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Hey Richard,

Sorry I circumlocutioned around your critical question . . . but it is a tricky question and pretty subjective ie "one man's grain is another man's noise"

Yes. I would say the IMAX print is a reference of what a good film print can look like. . . WHEN IT's PROJECTED REALLY BIG . . . altho I have seen 35 mm prints look that good that big but only at LA premieres.

So I guess IMAX is really BETTER than reference . . . . but my point is that 35mm print can truly approach that quality and lack of perceived grain if the prints and projectors are good . . . . and DVD's can approach that quality if they spend the time and the money on the transfer and authoring.

Also, "yes" to your observation of no film grain in the conventional sense.
To which I would add "no EXTRA film grain" ie from duplicating masters and crummy release prints. . . and yes, plus some digital magic.

The IMAX blow-up process starts with a scan of the original 35 mm negatives at extremely high resolution -- above 4K altho it's proprietary so they don't specify it -- then does digital up-scaling
and some tasteful grain reduction that doesn't affect fine detail because the resolution is so high and then outputs to full IMAX 65mm at a resolution of approx 9 or 10K

In other words they pretty much suck every ounce of image out of the film and working at such a mind-numbingly high resolution frequency allows the grain reduction to be MUCH more selective than the brutal frequency cuts we see on far too many DVD's {MGM.} PLUS IMAX
doesn't have to worry about MPEG-2 compression since their system is all UNcompressed which I think is likely the huge factor when compared to DVD.

But that's IMAX film . . . .

For the DVD it's likely going to look different. It'll look really good and much better than the first MATRIX DVD transfer but the order of magnitude of the difference probably won't be as stunning grain-wise vs sharpness and contrast as the IMAX difference. The DVD will likely be a 2K scan and then down-converted which is just simply not going to be as computer powerful or subtle process as the IMAX.

I've heard that Joel Silver has stated he wants to re-do the first film to match the quality of the sequels.
Oh good . . . another chance for us weenies to buy it again.

Thanks

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Richard F. Fisher

[HDTV Forum]

I've got One and Two on DVD. How do you think it will look on HD-DVD or even D-VHS?

Hugh Campbell

[HDTV Forum]

Like everything else...

Deeper color, better blacks, better shadow rendering and more detail. Could also mean getting closer to the original print.

I have X-Men 1 and 2 plus League of Extraordinary Gentlemen coming on D-Theater for the holidays! I LOVE D-theater!

Richard Fisher

[HDTV Forum]

Very interesting discussion on IMAX and how 35mm is upconverted to 65mm.

About a year ago I saw my first IMAX film. It was basically an advertisement for Austrialia, but very impressive.

Now for my question. I understand that an IMAX camera uses 65mm film in a horizontal format (similar I suppose to 35mm Vistavision). Any comments comparing the quality of an IMAX presentation using upconverted 35mm source material as compared to something originally filmed in 65mm IMAX?

Years ago it was common to film in 65mm and use the larger format for roadshow presentations and then make reduction 35mm prints for the smaller theaters. Movies such as Ben Hur, Lawrence of Arabia, MMMM World, were filmed this way.

Because of roadshow events in large venues being replaced with multi-screen theaters, the practice of filming in large format is a thing of the past, but now IMAX is bringing back the concept, however in the old academy standard aspect ratio of 1.33:1 rather than 2.55:1 as was done for Ben Hur.

Anyway, IMAX is quite an experience and I look forward to other opportunities to visit IMAX theaters.

Tom

[HDTV Forum]

Wasn't there a 70mm film used at one time years ago?

Chuck G

[HDTV Forum]

Chuck:

65mm is the width of the film in the camera. 70mm is the width of the film in the projector. The extra width is for the soundtrack.

Tom

[HDTV Forum]

D* is showing an IMAX feature this week in their pay per view HD package.

Jeff

[HDTV Forum]

to: Richard and the Forum Gang at large;

Neat to see people getting into good film theatre image quality.


What IMAX means for our systems is this:

-- BETTER IMAGES for our home theatres.

Feature films in IMAX raises public awareness of what good projected film image quality really can be.

Awareness creates demand and . . . . . image quality gets better. HOPEFULLY.

Gee, you didn't think the film studios and theatres would offer better image quality just cuz it's the right thing to do?


Also, RE: IMAX originated movies on DVD and HDTV

-- it's simple; The better the image coming in the better the image going out. . . and an IMAX image is WAY better.


SOME IMAX NEWS;

The third HARRY POTTER movie will be released in an IMAX blow-up in June on the same date as the 35mm release.

This is good.

AND . . . . there MAY be a THREE D - IMAX blow-up of
THE POLAR EXPRESS at some point. Now THAT I want to see.


RE: GRAIN and GRAIN REDUCTION

Richard posed alot of good observations and questions on this. Check out this article on it RE: restoring / cleaning-up the INDIANA JONES DVD set -- it's a really good intro.

http://www.apple.com/pro/film/lowry/

Also; TOM asked about the quality difference between IMAX prints sourced from 35mm originals and those sourced from 65mm IMAX originals.

The difference is NOT subtle.

65mm IMAX originals are AMAZINGLY superior.

The best way to answer the questions is to go see an IMAX blow-up and compare it to the trailers which are usually for IMAX originated films.

I saw a trailer for an IMAX NASCAR racing film before MATRIX THREE IMAX and it was incredible - so sharp and bright it literally looked three dimensional.


Best,

Greg

PS; OBTW To clarify; 70mm is ONLY a posative print format and 65mm is ONLY a camera negative format. There are no 70mm cameras per se.

The 65mm negative is printed to 70mm posative pint stock with the extra 5 mils originally set aside for SIX MAGNETIC sound tracks . . . but IMAX doesn't use them. Their sound comes from a separate audio deck synced to the projector.