It was pretty much impossible to get a picture that would really show you the extent of this incredible thing. This is a photo of the original edited 1948 35mm positive optical track for the film Muscle Beach, by Joseph Strick and Irving Lerner.
Those of you that know filmmaking and archiving at least a little bit will probably know what a bloop is. Basically, a bloop helps mask the sound of a splice in an optical soundtrack. Usually you cut a “V” shaped notch in the optical track where the splice is, so rather than a “thunk” on the track, you hear (or don’t hear) a sort of quick, hopefully graceful absence of sound that would last maybe 1/12th of a second, or even less, depending on what size notch, what film gauge, etc.
This thing, in the photo above, has got to be the longest “bloop” I’ve ever seen in my life. To be fair, it’s not quite a bloop, but a hand-applied tape masking used to create a fade-out/fade-in effect on the soundtrack. What you’re seeing above is a small fraction of the actual tape-bloop. It’s actually something like 20 feet long from end to end!