70 mm prints

[mattias]

the good thing about digital data (almost all digital data is represented on an analog medium by the way, be it celluloid, magnetic tape, radio waves or whatever) is that it has error correction that makes sure the data remains intact to a certain point where it just "disappears" completely. there's no gradual deterioration of the data at all (only of it's representation), and when the digital data disappears, you know this instantly and can switch to the optical track (you can often hear this at reel changes and other "dirty" passages).

/matt

[Alex]

Some Digital sources such as mini-dv use scanners that spin at high rates of speeds.

Can they fit digital onto a 70mm track, (and multiple tracks at that) without use of a high-speed scanner?

-Alex

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[Matt Pacini]

I'm not in my area of expertise here, but I'll ad something that my friend who works at VidFilm in Glendale Calif. told me.

(They do post production, foley, ADR, dubbing of foreign movies, etc. as well as restoration of old films, etc. They do most if not all of Turners restoration projects on the huge library of old classics he owns).

He mentioned to me that they put digital audio onto films in the spaces between the sprocket holes. So they don't take up any extra space at all. (I don't think he meant ALL films, but he was talking about common 35mm films).

Like I said, I don't do this kind of work, but he does, so he should know.

Matt Pacini

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[technicolour]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by MovieStuff:
The whole advantage of the CD sound is that damaged film won't result in pops or artifacts in the audio. I know some companies have been promoting the idea of digital sound tracks on 70mm prints, but they still have the problem with scratches and nicks in the soundtrack area. Digital or not, there are going to be problems when this happens. As it stands, the CD synch modules are cheap and seem to have a great track record. I think they'll be pretty much the standard until digital projection becomes a reality. Could be wrong, but that's my impression.

Roger<HR></BLOCKQUOTE>

I agree with Roger here, CD's definatly sounds the best way.
Do magnetic soundtracks suffer from all the noise and scratches like optical?

Matt said something about digital sound going inbetween sprocket holes, I think that is the timecode that syncs the film to the cd because that is how DTS surround works


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Jim

[Alex]

Once CD came out in the early 90's, it was a logical fit...however, Optical still makes sense as a back up....and additional Optical Tracks were being used as early as 1979 for StarWars...

I've heard of automatic switchback, where if there is any problem with the CD staying in sync (quite rare actually), the sound may switch back to the Optical film sound.

-Alex

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[Alex]

<BLOCKQUOTE><font size="1" face="Courier, Arial">quote:</font><HR>Originally posted by MovieStuff:
Hi, all!

Many of today's movies are shot anamorphic on 35mm and then printed up to 70mm unsqueezed. They do this for two reasons. The 70mm picture is much brighter and the 70mm print is projected aspheric with no special lenses required. Also, it means that only the original grain of the field negative is elongated by the anamorphic process; something that is critical to effects work and titling. The 70mm print is not only sharper than a 35mm print, but the grain of the 70mm print isn't elongated since anamorphic projection is avoided.

Roger<HR></BLOCKQUOTE>

Granted, those are two excellent visual reasons...

What about the optical audio capability...CD only came around in the early 90's....70mm was around way before then.

-Alex





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[MovieStuff]

Well, as was pointed out in someone else's post, there have been various flirtations with magnetic sound, both single and double system playback. Also, the fact that the velocity of 70mm is higher than 35mm as it roars through the gate is going to help out analog sound quite a bit. I really don't know for sure how many tracks 70mm had in the days before CD or digital encoding. Perhaps someone else can fill in the blanks on this. I would be guessing, but I would think a stereo pair with a Dolby encoded third rear channel was pretty common. Again, this is supposition on my part. I remember seeing "Raiders of the Lost Ark" in 70mm and hearing a rear channel plus the norma stereo pair. Same thing when I saw "Aliens" in 70mm. In fact, the laser disk on "Aliens" also has the same rear channel! When the drop ship crashed and a piece of metal whizzes past the camera and lands behind you; totally cool.

Roger

[technicolour]

Roger - In Dolby Surround Analouge do you know how the third surround channel is encoded in the two stereo channels or is the seperation done by some sort of circuit afterwards by a processor?



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Jim

[AlexGfromUK]

Back in high school I did a project on my local independant cinema upgrading thier sound system. I know that they intended to buy a digital soundhead for thier projector, as far as I know the optical data is in square blocks at the side of the image and within these is a pattern of small pixels representing a unit of digital audio information. The projectionist said that most general release films were now supplied with a digital sound track, and that was one of the major reasons for him wanting to upgrade, he could not take advantage of a better, or certainly more durable soundtrack. A good site to find about this stuff if you really want to understand it in depth would be www.dolby.com .They supply and fit processors and soundheads for digital audio, and I'd be surprised if you could'nt pull up an explaination of digital soundtracks on film release prints from there.

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[Alex]

I was given a two or three frame momento piece of a 70mm Star Wars a long time ago, you could actually see the optical tracks on it.

Wish I knew where it was.

-Alex

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