Film-Tech Forum ARCHIVE: Oz sound track

This is topic Oz sound track in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Greg Mueller (Member # 17) on 12-13-2000, 08:03 AM:

I just screened a reissue print of The Wizard of Oz. The analog track was terrible. I have not had any problem with the tracks on other film so I suspect it is the film and not the equipment, But, could I be over scanning and picking up the DTS track? (DP70) The symptom is buzzing and lopeing out of the left channel and general low volume levels. The buzzing etc seems to vary from reel to reel with little or none in one reel. If the analog track is goofed up does that mean that the DTS or SRD tracks are bad as well? I'm wondering if the whole film is misprinted

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Greg Mueller
Amateur Astronomer, Machinist, Filmnut

Posted by John Pytlak (Member # 331) on 12-13-2000, 08:17 AM:

You can check track position on the print by measuring it with a toolmakers microscope.

SMPTE Recommended practice RP 115 specifies the centerline of the DTS track to be 0.297 +/- 0.001 inches (7.54 +/- 0.03mm) from the reference edge of the print. The scanned width should be 0.005 +/- 0.001 inches (0.13 +/- 0.03mm).

Standard SMPTE 40 specifies the centerline of the analog track to be 0.243 +/- 0.001 inches (6.17 +/- 0.03mm) from the reference edge of the print.

Is your print a dye transfer print (dark gray, silver-only soundtrack)?

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

Posted by Gordon McLeod (Member # 33) on 12-13-2000, 08:43 AM:

Greg run the SMPTE track you should be able to actually see the track and the scanning through the viewport in the cell mount

Posted by Greg Mueller (Member # 17) on 12-13-2000, 03:32 PM:

Boy do I feel stupid.
Last month I completely gutted the Norelco and rebuilt it and somehow somewhere along the line I altered the tracking adjustment although I can't figure out how, as I didn't mess with that area. I was, in fact, reading the DTS track. I put in the test loop and hooked up the scope and it feels much better now. (And so do I.)

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Greg Mueller
Amateur Astronomer, Machinist, Filmnut

Posted by Greg Mueller (Member # 17) on 12-13-2000, 10:21 PM:

John
Sadly it's not a tech print. I did rescreen it just now. It sure helps to have the tracking where it's supposed to be. Sounds sweet.

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Greg Mueller
Amateur Astronomer, Machinist, Filmnut

Posted by Bill Purdy (Member # 202) on 12-15-2000, 09:26 AM:

Note to John: Those tool makers microscopes are pretty pricey. The technique I used in my lab days was to mount a chunk of the film in a slide mount and project it up on the wall. Assuming good and accurate Kodak film, I would then use the film width or one of the perfs for a reference measurement and could easily scale the track location from there. By making a bit of track with a high frequency tone on it, I could use a carpenter's framing square to determine azimuth.

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Bill Purdy
Component Engineering

Posted by John Pytlak (Member # 331) on 12-15-2000, 09:58 AM:

Bill Purdy said: "The technique I used in my lab days was to mount a chunk
of the film in a slide mount and project it up on the wall. Assuming good and accurate Kodak film, I would then use the film
width or one of the perfs for a reference measurement and could easily scale the track location from there."

Kodak uses those toolmakers microscopes as one of the many dimensional checks of perforator tooling and film. Your calibrated slide projector is a neat idea. You could probably project a calibrated reticle from Edmund Scientific to calibrate the magnification:
http://www.edmundscientific.com/

One idea would be to set the slide projector perfectly orthogonal to the screen to give a magnification of exactly 100X, as measured by the calibrated reticle. Watch out for keystone distortion. Then measure the image of the film on the screen. Basically a "poor man's toolmakers microscope".