(NOTE: This article has nothing to do with the Roxy, but we're including it just because it's a fun read.)

In the motion picture part of show business there used to be an unsung hero called a projectionist.

I call him "unsung" because he was that part of the theater no one ever saw. Or even thought about.

Except for when the screen went dark.

Or when the screen went white. That's when everyone began applauding, whistling or stamping their feet.

Or tried a combination of all three.

The implication, of course, was that the man in the projection booth had gone to sleep, allowing either the light to go out (dark screen) or the film to run out (white screen).

The stomping, whistling and applauding was designed to wake him up.

Actually, projectionists had precious little time for naps up there in the close little room where real show business was taking place.

When they weren't watching the screen and adjusting carbon arcs to insure even light on the screen, they were rewinding film that had just run through, threading up the next reel to be shown - and generally seeing that all systems were "Go" in the projection booth.

Projection booths were usually small, cramped, unventilated rooms high at the back of all theaters. And they always contained - besides, of course, the projectionist - two projectors and two lamp houses.

The projectors each contained a projection head, through which the film was threaded over a half-dozen or more sprockets, and a sound head where the film was passed over a photoelectric cell which read the gradations from white to gray to black, producing the sound. The standard projector was made by the Simplex people.

There was a lamphouse for each projector (made by the Peerless Company) containing the carbon arcs which produced the light, and a reflector which focused the light on the screen.

Film reels at first ran for 10 minutes, at the end of which time the projectionist performed what was called a "changeover," switching light and sound from the empty reel to the one he'd just threaded up.

The more skilled the projectionist, the smoother the transition. And the more attentive the projectionist to his equipment, the less chance there was of "losing" an arc and with it, losing the light on the screen.

And, in case you're wondering how the projectionist knew when film was running out and how he knew when to switch, the last part of this lesson is about cue marks.

Those are those little black or white circles which appeared every now and then at the upper right hand corner of your screen. When you saw the first one you started the fresh film through its machine. When, a few seconds later, the second cue mark appeared, you switched sound and light from one machine to the other.

It was a changeover - and nearly always, a smooth one.

But no sooner was it done than the projectionist was at the business of rewinding the old reel of film, threading up the other machine, checking his sound and light - and having (just possibly) a cigarette before time for the next changeover. ("No smoking" signs in projection booths, it was a fact of life, did not apply to projectionists.)

So much for behind the scenes in show biz - but for lagniappe, let me tell you about those tiny holes spaced about a half-inch apart in every theater screen today that you probably never dreamed were there.

The holes are there so that the sound (which comes from horn towers behind the screen) can get through to the audience. Otherwise it would be muffled and blurred.

Finally: Did you know that while you're sitting there watching a film the screen is completely dark half the time?

Like if the show is two hours long, there's a picture on the screen only one hour?

The reason? Okay - one of those sprockets I mentioned earlier is called the intermittent sprocket because it allows one frame of film to be shown, then moves the next frame into place. While the frame line passes through the apertures in the projection machine, a timed shutter cuts off light until the next frame is in place, thus giving the illusion of motion to what is actually a series of still photographs shown, one after the other, for the length of the picture.

But don't try to get in for half price just because there's only a picture there half the time.

It didn't work for me, either.