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Thread: Videotape splicing tool - photo

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    Altair's Avatar
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    Supporting Member jdurand's Avatar
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    jdurand's Tools
    There's a tool for video and audio tape? I just used a table, tape, and a razor.

    Of course when I was a projectionist we had the solvent based 35mm splicers, we'd go through and cut out all the tape splices other people had done and put in solvelt ones that wouldn't pop going through the projector. I may also still have one or two 8mm ones of my fathers.

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    Supporting Member NeiljohnUK's Avatar
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    I remember splicing 1/4" r2r tapes with the smaller version, digital recording is just so much easier...

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    Supporting Member Paul Alciatore's Avatar
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    Paul Alciatore's Tools
    When I first started as a TV engineer back in the 60s one of the things my boss taught me was how to splice video tape. Video tape at that time meant 2" video tape. The TV industry was in the state of change from programming on 16 mm and 35 mm film to video tape. Color video tape was still a young technology. Actual editing of programs, commercials, and other matter was done electronically, using two or even three video tape recorders but sometimes a program tape would physically break and had to be spliced together.

    It was a skill and almost an art.

    Splicing video tape is not like splicing audio tape. Audio tape has one or more tracks that run parallel to the length of the tape and a splice can be easily made with either a square or diagonal (45 deg) cut. The diagonal cut provided a very short fade from one to the other and is the preferred method.

    But video tape has the video tracks at an angle to the length of the tape: with two inch formats, which broadcast TV used, that angle was almost but not quite 90 degrees. In addition there were one or more audio tracks and what was called a control track that ran along the edges. If you used a simple square cut as was used for audio tape then the video tape player would lose synchronicity at that point and the picture would break up for several seconds. In order to make a splice that would play back without such an interruption you had to make the cut at that exact angle to put it between two of the video tracks while also preserving the phasing of the control signal in the control track. To do this you had to use a "developer" that consisted of a very finely powdered magnetic material in a fast drying solvent. This developer was brushed or dropped onto the tape to show the magnetic patterns there. Those patterns were lined up in a special splicing fixture that had fine feed knobs on each side and an optical graticule. Then a cutting guide with a slit was placed over the tape and a brand new razor blade was used to make the cut on both pieces of tape at one time. The splicing tape was applied to the back of the tape while it was still in the same position as when it was cut.

    The splicing block I used was made by Ampex who also manufactured the professional video tape recorders. In addition to the fine controls for positioning the tape, it also had an magnifier so that the recorded, video tracks could be easily seen. They were only 1/100 inch wide and the space between them, where the cut had to be made was only half that.

    The splicing block shown in the photo seems to be for one of the helical formats of video tape. For helical formats the splice would be several inches long if made between the tracks as was done with the 2" broadcast formats so they returned to using a cut straight across at 90 degrees. This produced a top to bottom wipe type effect in the video when it was played back. If the splice was to play without disturbance the control track had to be kept in phase just as with the broadcast formats.
    Paul A.

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    Supporting Member jdurand's Avatar
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    jdurand's Tools
    I did my splicing first on 8mm home film, then straight to 35mm in a theater chain as a teen. Also spliced audio tapes for people and have repaired video tapes, I actually have a Hi8 tape I need to fix.

    After that I got into computers and didn't touch video or audio tape for a long time, just 9 track digital tape and paper tape.

    I didn't get into SMPTE until the digital transition was starting, got to hear all the moans and grips from the RF guys trying to make the transmitters work and so on. I designed the first digital interface for one of the LCD manufacturers, the first demo (the standard cheerleaders) shocked the upper management when I could freeze it with perfect quality and no flicker, back up and continue.

    At that time the video source was SMPTE 259M if I remember right, digital coax from a high end computer running Adobe Premier. That stuff sure cost a lot of money back then!

    The far gone days when we watched TV with our pet dinosaurs.


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