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Looking to learn about film leaders

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  • Looking to learn about film leaders

    Hi everyone, I just joined and was hoping you could help me learn a bit more about film leaders and tails.

    I've looked online and I'm struggling to find out what a lot of it means, the IEEE documents just go on about the technical details of the leaders but not what each frame means for a projectionist.
    If you know what these mean, or know where I can learn more, please let me know. I'm familiar with 35mm film, but I've never worked in projection.
    Also what does "common sync", and "splice here" mean?

    Some frames I would like to know more about below, and what they mean to a projectionist:
    ‚Äč FZzuNkP.png

  • #2
    "Head" and "Finish" are the beginning and end of the reel.
    That's how you know you've got the film the right way up before you thread (HEAD) or if you are at the end of the reel. (FINISH)

    If you are splicing reels together or you are using a platter to show a movie, you'll splice the tail of the first reel to the head of the second, and so on.

    If you are using reels/chaneovers, you use those frames to tell that you're threading the right way. (Or if you've got it wrong and need to rewind the reel.)
    Also, if you are using reels, it is common practice to return the film on shipping reels with the tails out. That makes it easier for the next guy to set up the movie.

    "Picture Start" and "Sound Start" signify the beginning of the picture or the beginning of the soundtrack, respectively.
    The picture and sound are spaced 21 frames apart in order to account for the physical separation beyween the picture in the film gate and the scanning point of the soundtrack.

    If you put the frame "Picture Start" precisely in the film aperture then thread your projector correctly, the "Sound Start" frame should be exactly at the sound scanning point. This is one way to practice threading so you can learn how to do it exactly the same way, every time. It's a highly important skill to learn if you want to put on a professional looking presentation.

    The "Pop" frame is kind of a test to know if you've got your threading right. There is a fraction of a second "blip" in the soundtrack. If you've got everything right, you'll hear that blip at the exact moment that the "Pop" frame appears on the screen. I think it's also used in the lab to ensure that the film is made correctly but that's above our pay grade.

    If you see a "Cut Here, " "Splice Here" or if you have a foreign movie "Couper" (French for "cut") that is the place where you are supposed to cut the film when you splice reels together. This is not necessarily true because, if somebody else has spliced the film before you, there might be frames missing. I think it's better to say that the "Cut" frame is the place where you should start looking for the right place to cut, not necessarily the exact place.

    The frames with the numbers on them are time codes. If the film is made via video transfer, that's the time code of the source media that was used to make the film and the numbers signify Hours/Minutes/Seconds/Frames where they started. This is something that's nice to know but, for the average projectionist in the trenches, it's not important.

    There are also come "Countdown" frames that are used in reel-to-reel projection in order to synchronize changeovers. A good projectionist will experiment to determine how long it takes his projector(s) to come up to speed from a dead start. He will know which number in the countdown to thread his projector on so that, when he hits the switch to make the change, his incoming projector will be dead-nuts in time with the outgoing projector. Done well, the audience should never know that a change was made. It's a badge of honor to be known as a "dead eye." (or some other funny name) That's a guy who never borks his changeovers and always hits them spot on.

    A lot of those marks are used more for studio projectionists in screening rooms or for guys in the lab who make the film but it's always good to know what they mean.


    • #3
      Another important thing about film leaders, you will encounter two main types, one is the SMPTE Universal leader(Society of Motion Picture and Television Engineers) and the other known as the "Academy" leader. (Many foreign films use a version similar to the Academy leader.)

      The SMPTE leader numbers are a countdown in seconds to first frame of picture, and can be recognized by the "clock" or "radar" surrounding the number with a thin line that sweeps around to the next number.

      The Academy leader's numbers count down in FEET to the first frame of picture. That is a significant difference in timing for changeover operations.

      For the projectors I ran at one of my screening rooms for example, on the SMPTE leader I started with the "5" second frame with the sweep at 45 degrees. Academy leader I started with the 7 foot mark (IF I am remembering correctly, it has been 10 years since I last ran changeovers.)

      Both start points will vary depending on a number of factors, such as how fast the projectors get up to speed (and I had one Bel Aire room where they started at different rates, so each machine had a different start frame), your reaction times to seeing the motor cues, and if any frames were cut from the leaders either between numbers (really annoying, I would usually make a new start number with a grease pencil) or at the start of picture area. It is always wise as a projectionist going to a new or unfamiliar screening room to do a few "test" changeovers if possible to ensure you can get them spot-on. With a bit of experience you can do a changeover literally down to the frame.

      A third type of leader commonly used for threading up platter systems was a version of the Academy leader, with about 15 or more feet of just frame lines, leading (pun intended) into the Academy countdown starting with 11 feet. It was usually light blue and pretty rugged, but any brain wraps would stretch it out to the point of being unusable. It was one of the earliest uses of mylar for film, before mylar prints started to become popular. Someone on here will remember the brand name for that leader which escapes me at the moment.


      • #4
        Agreed with everything said above. Also, 16mm uses a different offset for the optical soundtrack (26 frames vs. 21), so most leaders have separate "16 sound start" and "35 sound start" frames. With 35mm, the standard practice is to thread with the sound advanced 20 frames (even though the lab advanced it by 21 frames) to provide correct synchronization in a typical movie theatre seats (because light travels faster than sound). In a screening room, one would use the 21-frame standard.

        Note that the "dot" frame has a "dot" on the optical track. The picture and soundtrack are printed from different rolls of negative film, and dot is so that the lab workers can verify that they were printed in sync. I've seen the "XXXX" frame used this way as well (four X's in the track negative).

        Note that, with either type of leader, in 35mm, the "Picture Start" frame is exactly 12 feet from the first frame of picture for that reel. The last number on the countdown (either "3" or "2") will be exactly three feet from the first frame of picture (with 47 frames of black between them). There is normally a "beep" (aka "2-pop") that accompanies that single frame (as noted above), which is a way to verify that the soundtrack was properly printed in sync with the picture. This is normally a single frame of 1kHz tone, but it really could be anything beep-like. Some films have "tail pops" as well, usually with an upside-down "2" or "3" located three feet from the last frame of picture.

        The platter threading leader that seems to be most common is "NT Audio Visual," although there seem to be (or have been) multiple manufacturers of it.


        • #5
          Originally posted by Tony Bandiera Jr View Post
 will encounter two main types, one is the SMPTE Universal leader(Society of Motion Picture and Television Engineers)...
          I'm sorry but I can never hear that phrase without thinking of Frank Zappa's song "Baby Snakes!"

          I first heard the song in the late 70's but didn't fully understand what it meant until I started working in theaters. I mean, I knew what SMPTE was but didn't put two and two together until then. The first time the guy who trained me used "SMPTE Leader" in a sentence, I replied:

          Dit-dit...Dit-dit...Dit-dit...Dit-dit!... That sands for SocietyofMotionPictureandTelevisionEngineers!

          His answer was, "It keeps you insane!"

          Now you've got the earworm, too!


          • #6
            This thread made me recall my pre-platter projection days... I had kind of forgotten about how we used to have to thread "to the 7" on the leaders. I was very good at changeovers but I got a bit of a nervous feeling every time I did one. I figured that was a good thing, kept me on my toes.


            • #7
              And then you get a platter and wonder what to do with all of your free time.


              • #8
                Well when we bought this place, there were three projectionists -- me and two teenagers. The 3 of us would alternate nights so we would have evenings off to be young and reckless. Once I became an owner with actual responsibilities, I relegated the projection booth duties to the two teenagers so I could keep an eye on the auditorium and boxoffice. But I did do the bulk of my own film work after we got our platter.


                • #9
                  Other than the footage or second count-down numbers, most of what is on the film leaders is there more for
                  the benefit of the film laboratories than for the projectionists.