Film-Tech Forum ARCHIVE: Splicing 35/70mm Magnetic Track Film

This is topic Splicing 35/70mm Magnetic Track Film in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Erick Akers (Member # 875) on 11-04-2003, 02:47 PM:

It's been quite a while since I have done any splicing of mag track film.

As I recall we used to have splicing tape with mag strip for preventing the audible pop through the mag reader. Is this still available?

I also recall hearing of a splicer that angle cut the audio tracks only.

I checked F-T archives with no luck, any suggestions?

Posted by Darren Briggs (Member # 1071) on 11-04-2003, 03:04 PM:

In many cinemas that suffer from drop out as the slice goes through, but i have never had this problem, and i just use standard clear tape. Maybe other sites have the tension wrong on the mag heads and the slice makes the film jump up over the head and hence loose the signal.

Darren

Posted by John Pytlak (Member # 331) on 11-04-2003, 03:21 PM:

Does anyone make a tape splice across the full width of the print on the emulsion side, but only tape the image area on the base side, leaving the striped areas uncovered?

I do recall that it was "good practice" when making cement splices on triacetate striped prints to make the splice such that the overlap "slipped over" the mag heads, rather than "bumped into" them.

Posted by John Walsh (Member # 168) on 11-04-2003, 04:36 PM:

For the ever-popular Neumade splicer, they made a steel guide to allow you to cut the tape so it only covered the image area of 70mm - not the tracks.

The first time I used it (I was used to cement splicing at the time) I ran the print through a JJ-2, and it sort of "folded" above the gate, making a "POP!" noise. Didn't break, but it did kinda scare me, and ever after, I just put the tape across the entire width, both sides.

The sound is recorded vey "hot" on 70mm, so even with a peice of tape across, I found the breif, slight reduction in sound to be well worth not worring about if it would come apart.

Posted by Pete Naples (Member # 761) on 11-04-2003, 04:47 PM:

JP I was experimenting with an ultrasonic splicer for 70mm mag, and that good practice you mentioned seems to be the only way, in fact I found you had to remove the mag on the 'under' side of the join to get it take properly. Once perfected it's the usual thing you'd expect from an ultrasound splice. Great for test loops and repairs to films, but not so good for reel joins.

Posted by Erick Akers (Member # 875) on 11-04-2003, 07:03 PM:

Thanks for the response to this inquiry.

Mr. Walsh, you are indeed right. I just found my neumade splicer and this is indeed the case.

Also while digging around, I found some peel and stick magnetic reader tape that I had planned on giving a try.

Engineering sound is my field of expertise, pops and clicks just bug the hell out of me.

Pete, I just purchased a Metric 3070 Ultrasonic Splicer and that's good news for me, and though I am not quite operational, It's slowly coming together.

Again, my gratitude to all, also to you Mr Pytlak.

Posted by Gordon McLeod (Member # 33) on 11-04-2003, 08:14 PM:

CIR provided the cutting template to prevent the tape from covering the mag stripes

Posted by Steve Kraus (Member # 476) on 11-04-2003, 09:52 PM:

Isn't there greater risk of a head clog from the cut edge of a track going over the head than the brief passage of tape? On the other hand 35mm fullcoat and stripe were/are always taped on the backside only and that was a proven technique.

Posted by Stephen Furley (Member # 1277) on 11-05-2003, 05:07 AM:

Fullcoat doesn't have to cope with the intermittant movement and tightly curved, unsupported film in the loops that a projection print does though, it's path is only curved where it passes around a roller of sprocket.

Posted by Scott Norwood (Member # 30) on 11-05-2003, 06:35 AM:

Splices in mag fullcoat are normally made at an angle (to avoid "popping" when the splice passes across the heads) and with extra-strong white tape (the kind that everyone here hates). Thus, whatever approach works for fullcoat isn't necessarily applicable to release prints.

Posted by Steve Kraus (Member # 476) on 11-05-2003, 07:20 AM:

Straight cuts are far more common. Come to think of it I haven't seen a diagonal cut in a long, long time. But then again mag is not in the path for final audio since it's just for dailies and transfers of mixes to be played locked to work or answer prints.