Cinematography Mailing List - CML

: 30 Seconds - Tone & Bars

We’ve always run Tone & Bars for thirty seconds at the head of each tape, I think it’s pretty universal. Is this still necessary?

Today’s digital equipment is far less likely to drift and I’m not at all sure that a full thirty seconds is required even if some adjustment is needed.

Is this just a holdover from film, running a bit of stock to guard against damage to the negative at the head/tail of the roll? Could there be a similar problem, with more drop-out potential with video tape? Is the thirty second rule a ghost from the days when we were constantly setting up our tape decks?

I’m now running thirty seconds on my first tape of a job and then ten seconds on each additional tape. Am I getting some “free” stock, or am I entering dangerous waters?

Best regards to all,
Leo Ticheli


It's still very necessary. Even with digital equipment, here are some good reasons :

1) Even HDCAM and D5 decks have settings that allow an operator to override the factory preset levels. If those settings are off, bars let you see this
instantly on a scope.

2) The head/tail of a tape is the most likely place to get damaged. Don't put critical program material on it.

3) ABC, NBC, CBS, FOX, MGM, Universal, Sony, & Warner Bros. all require bars at the head of delivery masters, because most NTSC broadcast delivery is still done from analog masters. ABC, for instance, is still D2.

4) Bars aren't just for tapes and decks -- they are for monitor calibration as well, and monitors are far from stable from facility to facility.

5) Tone isn't just for tapes and decks -- it's to verify the integrity of the playback chain.

6) Almost every video editor I know (me included) does some stupid human trick during Tone to harmonize with it, make fun of it, or otherwise be silly. It would take away an essential geeky moment in the editing suite if you lost it.

Lucas Wilson

HD/2K Online Editor
Santa Monica / Hollywood

I tell my Assistants that when laying Bars and Tone that they must shoot for 30:00 exactly every frame over or under is a 6 inch putt from a "Hole in One"

This is a display of Mastery.

B, Sean Fairburn

Thanks, Lucas, Sean,

I was speaking only of field tapes, not masters; we always put :30 bars & tone on them for setup.

I think I¹ll continue to use the :10 bars & tone on all field tapes after the first one, with the full :30. If I do run into a problem, I¹ll report it.

Best regards to all,

Leo Ticheli

Leo, I'd strongly suggest sticking with the :30 on each and every tape, if for no other reason than the safety factor of avoiding creases at the beginning of the tape. What's another 20 seconds to err on the side of caution?

George Hupka
Downstream Pictures
Saskatoon, Canada

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