Film-Tech Forum ARCHIVE: Test film combo ideas

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Posted by Jon Bartow (Member # 241) on 05-11-2001, 10:12 AM:

Here are some ideas to bounce around that might make the field tech's life a little easier:

SMPTE 35PA (RP-40) with a dolby tone analog/digital sound track (I know that Schnieder/Lucasfilm's version has all of the sound tracks on it, but those are only channel id, not something that actually might be useful in the real world). Perhaps on the same loop a DTS test track (to allow hooking your scope to the reader and aligning the reader properly. Only on the readers that no longer have/never had a sticker ).

Buzz track on one side and Left/right on the other. This would allow for a "mobius loop" to be created. So, with an eight foot loop of film one would actually get eight feet of each test track at a time rather that only four feet. Of course this would require the labs to make sure that the sound track could be read correctly from either side of the film (emulsion or base). We could also have perf numbers printed in the image area for setting reader offsets.

(Maybe all of the test film could be encoded with an SDDS track that contains a self-destruct command for the SDDS equipment )

Posted by John Pytlak (Member # 331) on 05-11-2001, 01:27 PM:

The orientation change with a Mobius loop would make most tests invalid, since sound focus, film curl, etc. are all set for running with the emulsion side of the print facing AWAY from the projector lens, as specified by standard SMPTE 194.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
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Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
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Posted by Aaron Sisemore (Member # 145) on 05-11-2001, 05:33 PM:

Having the soundtrack on both sides of the film would render the RP40 useless as anything but a focusing aid, as you wouldn't be able to use the full width of the frame (where the second soundtrack would invariably be printed) for cutting apertures, centering turrets, etc.

Aaron

Posted by Steve Guttag (Member # 268) on 05-12-2001, 09:47 AM:

First 35-PA is a camera original thus, putting a soundtrack on it would require making a duplication ...

... next comes the reject rate...35-PA has a tough enough standard (and I am find that it has a tough time reaching more often now)...all of the sound test films have their own reject rate...when you combine to one film, you grow the problem geometrically. Therefore, to get a film that could actually be trusted, it would be prohibitively expensive....RP-40 is knocking upwards near $4/foot in 50' quantities!

What good is a test film whose accuracy can't be trusted?

Then there is the reality of how many times do you tune your sound but not have to work with the picture or vice-versa? You probably wouldn't want to keep paying for a more expensive test film to do half the job.

I think it is better to have specific test films to to specific jobs and only consume them as needed.

What this industry really needs is QUALITY CONTROL on the test films we have...35-PA is wanting, the color Cat.69P has poor HF response (it was worse before REV1) and isn't uniform from batch to batch. Often Cat. 97 and P35-BT don't agree with each other (more apparant with the reverscan readers)...in theory P35-BT is more accurate though many gripe about the noise created by it's manufacture (I actually prefer it since the "blip" shows on the scope and confirms both channels are operating in absense of tone).

I've had a bad test film week (does it show? )

Steve

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"Old projectionists never die, they just changeover!"