Most likely color changes that occur from one reel to another (in theaters that still use more than one projector) are from color differences between the lamps inside the projectors. Many a time I was in a theater where every other reel looked “warm” between every other reel looking “cool”.
And yes, change-over cues last only three or four frames, not seconds. From DuArt, one of the leading film post-production labs:
I think you must be a very observant and picky person (as I am, so don’t take that as an insult 
). For old films with frequent streaks, flaws, splices, holes, jumps, burns, etc., a small dot on the right corner of the screen once in a while doesn’t seem like much to someone who is more interested in the characters, plot or music.
Besides, not all burn marks (at least years ago) were the same, rigid, uniform oval size/shape/color, probably due to diff editing shops and maybe deliberately to make them look like a true flaw to everyone except the projectionist.
For the record, it’s in the Dead Marshes, and both my companion and I commented on it. I thought it was a flaw until Tangent and Masuro checked in. Didn’t see digits/letters in the California screening.
I got to see it very visibly demonstrated by the inept theater I saw TTT in. The tell-tale mark would appear, and a second later the movie stopped for a quarter of a second and suddenly started again. Friggin’ inept twits.
Zagodka, if that was a fairly new theater, it sounds like someone spliced the reels together with leader inbetween!
Musicat, you’re correct, the mark is contunued for three frames to give a little time time for the projectionist to react.
Usually it is a distinct oval, I never thought of it as designed to look loke a flaw. And it doesn’t look like one.
Also, the second set IS on the last 3 frames of a reel. The first set, 10 seconds in advance, is the cue for the projectionist to start the second projector, because it takes several seconds for the film to get up to speed and stabilize (hence, the 10 second count-down leader you see at the beginning of most reels – you cue up the reaal so the number ten is in the film gate). At the second mark, you hit the changeover control. That shuts the iris (that’s not the right name for it, but I’ve forgotten) in the first projector and simultaneously opens the second for a relatively smooth transition.
Occasionally you will see 3 sets of marks, when a projections has added an ever earlier crude set with a marker as a “get ready” warning. Typically, though, the first set means “roll the next projector”, and the second set means “change NOW”.
Not according to the DuArt site quoted from by Walloon earlier:
According to Greg Pak’s film calculator, 1 second of 35mm film at standard speed of 24fps is 18 inches of film. This would make “1 foot 9 frames” about 1.4 seconds, a little shorter than the 3 seconds I was estimating, but 33 frames exactly, not 3 frames.
Darn. As Barbie said before she became politically correct, “Math is hard.”
1 foot of 35mm film = 16 frames.
Therefore, 1 foot 9 frames would be 16 + 9 = 25.
At standard 24fps (frames per second), that would be about one second of running time. So there would be about a second of leeway/overlap between the final projector changeover signal and catcalls from the audience.
And I curse this thread forever, in as much as I’d only ever vaguely noticed these things before and certainly never paid any attention to them and after having read this thread went and saw Chicago and LOTR and sat there in utter agony trying to force myself not to watch for them. I’m sure I saw every last bloody one of them, too. Though, in LOTR at least, it would have been pretty hard not to notice the reel changes, coming, as they did, accompanied by completely obvious colour saturation changes. I don’t know if that was the print, or the projectors, but I’m sort of surprised given other content of this thread that a big, fancy, new theatre like the one I was at would have not been running the whole film off a single reel.
Musicat…Dont know what light source would be used now. Also I was wrong about them burning sulpher–PU!! I think they burned CARBON sticks… something the old coal miners burned also. Could these be arced across for a light??
Oh Boy! A thread where I can bore people with talk about my prior life as a projectionist! (a rare opportunity)
First, I suppose I should at least add something to the discussion about those change-over dots. It’s about the shape: Why are they oval? It turns out that most big-name films are filmed and projected with anamorphic lenses – the actual image on the film is fairly squarish in shape, but they stretch it horizontally to fill the screen. If you look at a piece of this film, all of the actors are tall and thin (this allows the image to completely fill the square area of the frame, instead of appearing on the print as “letterbox”, thereby increasing the resolution). I presume that the change-over dots are simply holes punched in the negative at some stage in the filmmaking process, thus resulting in rough black circles (white on the negative). When these are projected through the anamorphic lens, they get stretched horizontally and become ovals.
Many films are still filmed with “Flat” lenses which do not compress the image (thereby losing some of the available area of the frame). On these films, the changover dots are circles instead of ovals.
About those platters… Here’s a picture of how these things work today.
I always found it fascinating that they had used the same principle (draw the film from the center of the reel and wrap around the outside) as was used for 8-track tapes.
As an 8-track plays, each coil that is wrapped around the outside has to tighten slightly over time so that eventually it has the diameter of the center core. Film doesn’t do this as easily; hence, they usually go from one platter to another. Even though they lose the “continuous loop” aspect, there is one cool outcome: when the film is finished, it does not need to be rewound. The beginning of the film is always at the center of the platter.
There are some platters out there that run in a continuous loop. They use arms that pack the film as the platter turns. Besides the fact that they cannot hold as much film, I don’t like them for other reasons: These platters encourage projectionists to leave a machine on auto-pilot, letting the machine get dirty throughout the day.
At my theater, we usually ran two prints of major films in four theatres. I remember showing “Ghostbusters II” with a single print in three theatres, and one of the old hands said that we showed “Fatal Attraction” with a single print in five theatres.
Our theater had two electrical busses running the length of the projection booth. Each projector had a “synchronize” switch that could be flipped to be on bus A or bus B. When any projector on the bus was started, all of them would start, with their motors precisely synchronized. Likewise, their failsafe mechanisms (which kill the machines if there is a film break), were all interlinked.
With this arrangement, we could run up to two sets of linked projectors. It was a scary business, and I remember preparing drawings showing how to thread the film through the pulleys on the ceiling to help everyone remember the setup. Basically, once you got all of the machines threaded, you said a brief prayer and hit the switch. We never used the timer to start one of these Rube Goldberg contraptions.
As mentioned previously, the head and tail of each reel (usually 6-7 reels) is removed when the film arrives at a theater and all of the reels are spliced together. When the film is “broken down” at the end of its run, the heads and tails are reattached. This process, repeated a few times, causes the first and last few feet of each real to get kind of grungy.
We originally used bright yellow splice tape, the easier to find it when it came time to break the film down. The splice simply appeared on the screen as a black frame with a slight hiccup. For film repairs, we always used transparent tape; you probably have never noticed a repair in the middle of a reel, even though any film that has been showing for a few weeks has a few. About 12 years ago, United Artists switched us over to a transparent reel splice tape to join the reels, with a twist: the tape glowed in ultraviolet light. They shipped small blacklights to all of the projectionists so that we could shine the light on the film as we were breaking it down in order to find the reel splices. In addition, I used to color the edge of the film for several inches around the splice with a highlighter, as they glow nicely under blacklight and are invisible otherwise. These splices, done properly, were virtually indetectable.
Let me tell you about… Xenon bulbs. Here’s a page showing a guy holding the mother of all xenon bulbs. As the page says, ours (more typical) were in the 2,000-3,000W range. Here’s a page with a lamphouse, showing the bulb in situ.
Get a load of the gear the guy on the guy is wearing. These things are downright scary. They are made of quartz, as thick as a Coke bottle. They contain Xenon gas under high pressure. When one of these puppies explodes, it sounds like a bomb went off. And explosions are not uncommon. After a few thousand hours, they sometimes blow of their own accord. Our lamphouses were not horizontal like those in the picture – horizontal bulbs tend to blacken on one side – our bulbs were pointed straight up, with a 45-degree mirror at the top to redirect the beam. When one blew, the top electrode inevitably smashed the mirror, a very expensive half-silvered mirror that lets the heat pass through, and the quartz shards always scratched up the “salad bowl” reflector.
Changing one was tricky, I always felt like I was on the bomb squad or something, carefully handling a suspicious package.
We always smashed them prior to discarding them, to protect unsuspecting dumpster divers: the approved procedure was to wrap them in many layers of newspaper and then strike them with a hammer.
I believe they are called “carbon arc” lamps. The ones I knew (we’re going back to the 1950’s, now) in 35mm projectors were two electrodes enclosed only in a metal cover which we had to open sometimes to check on them or replace the rods. If they grew too far apart, the light grew dim or went out, but they sure were bright when they were working.
minor7flat5, I didn’t see your post before I uploaded mine, which was really answering STARR’s.
I wonder if your experience (with projector lamps) is more recent than mine. I distinctly remember the carbon arc rods in more than one 35mm theater setup, and I think I saw a 70mm one.
I’m sure your theory about the round->oval shape of the punches is correct. In Hollywood, during such motion picture production processes like recording a musical score to match the film, the editors prepare the working print using hole punches exactly as you describe to help cue the orchestra conductor.
However, my experience in this field is not recent, either, so maybe something different is used now.
Question and hijack: what does “bdfa” mean to you?
What a terrific post, minor7flat5! I’ve always been interested in this subject and have been following this thread intensely. Your post just brought it all together.
Would you believe when I first learned to make up films the manager showed me how to run white shoe polish along the top of the splice for several feet to make it easier to find upon teardown? As you can imagine our prints ended up looking like crap as the shoe polish crumbled off and made a mess of them.
**
I was actually standing next to a projector once when the Xenon bulb blew and it was seriously terrifying. There was a huge “BOOM” and a shower of glass came out the bottom of the lamphouse. I was shaking for hours afterward!
I was working in this field at the beginning of the 1990’s. To the best of my knowledge, xenon bulbs have pushed carbon arc lamps aside in pretty much the same manner as platter systems have superceded twin-projector setups.
It makes sense: Why constantly fuss with carbon rods when one can run a xenon bulb, carefree, for a couple thousand hours (and maybe get one great BANG at the end!)
Nothing…
Either it is something from before my time, or it has been lost in the haze of the past decade. Care to fill me in?
Hint: look at your SDMB name.
Spell a B minor seven flat five chord.
:smack: My brain doesn’t perform cross-context queries very well.
A quick glance at my guitar shows that you had to hunt around a bit before you found one without any telltale sharps or flats 
minor7flat5, I just wanted to echo the other folks and thank you for that informative post-- fascinating!