A friend and I got to talking about arc lighting, and I remarked that the only place I still know of where carbon arc is still used is in big spotlights. Now used only for the glitz of world premieres, carbon-arc lighting used to be commonplace; the commonest of places was in movie theatres. Carbon-arc lights give a wonderful, wide-spectrum light that (still is) the perfect match for film projection. Nowadays, theaters (note the different spelling) use xenon lamps – they’re far safer now and can be handled by ameteurs. But the light they give is still no match for carbon-arc.
Which brings me to carbon-arc movie projection.
The art and science in the job of Theatre Projectionist is one that is fast fading. But my good freind Dan was a Theatre Projectionist. I remember one Saturday morning I was invited to visit him at work. I showed up at the Fox Theatre, and he met me at the door; then led me up to the projection booth. He was doing maintenance on the projectors prior to the afternoon matinee. He had been polishing the mirrors (solid silver bonded to a copper carrier) with Bon Ami, cleaning the ash and slag from the carbons (takes two of them to create the arc) out of the bottom of the lamphouses, and making all ready for the night’s work. Checking and oiling the intermittents, reel drives, and so on, even checking to make sure all reels were properly rewound. He told me that occasionally he’d check the chimneys above the projectors to make sure the air was moving through them – when the projectors are running, burning the carbon puts out a fair amount of smoke. There was a chimney for each projector to catch that smoke and get it out of the booth. However, the booth still unavoidably smelled a bit of burned carbon.
He showed me the ‘carbons’ for the projectors. These were the consumable terminals where current jumped to form the arc, and were round, about two feet long, and looked every bit like a pencil that was as big as your thumb. He explained to me that they came in various grades and the theatre owner (his boss) always bought the best he could. These carbons came with a copper jacket, and that jacket was what created the slag in the bottom of the projector as the carbon burned. The positive was the one that burned the fastest, and it had a special holder to ensure its proper burning. The negative was the expensive one; solid-mounted in the projector, you only replaced it when it was too short to work all the way through the night; and they lasted for about three weeks or so. The positive carbon fed into the projector from the back, and had a chain-drive mechanism on it to both turn it and slowly feed it into the arc. The feed was regulated by a wire-wound rheostat on the side of the projector, while the turning was a constant rate. Dan would go through one and half or two complete positive carbons a night, depending on the length of the movie. He’d change carbons in one projector while the other was running.
Dan led me down four stories’ worth of stairs and ladders, and I helped him clean the commutator on the big dynamotor in the basement – the commutator was as big around as your leg, and the dynamotor stood a little less than waist high. We polished that commutator with emery cloth until it shone, wiping it down with a clean towel to remove the dust and any residual abrasive from the emery cloth. We then inspected and dusted off the AC-powered side to make sure it had no problems.
We then went all the way back up to the projection booth to check how the arcs burned in the projectors.
Arriving once more in the projection booth, he went over to a small control panel on the wall between the projectors and pushed a big START button for the dynamotor. The projection “balcony” had doors on both sides. One was for access, the other was called ‘the sound porch.’ The sound porch was for the projectionist to step out into the theatre space where he could check the sound quality and then adjust it as necessary for both the movie sound and for the crowd. Sound in a theatre changes dramatically in volume and equalization between a sparse house and a full one, and Dan was always making sure the theatregoer had the best experience possible.
When things were going to be quiet in the booth, Dan would open both doors up to get rid of some of the heat. Through the door of the sound porch, we could hear the dynamotor rumble to life, sounding like something out of a monster movie; and the voltmeter on the panel eased its way up to 12 volts as the dynamotor spun slowly up. He reached down to the sink, and opened a tap. Water began to flow through hand-bent quarter-inch copper pipes that snaked across the ceiling, one each going to the two big projectors, each with a return loop that came back across the ceiling and ended at the sink. As soon as the bubbles quit coming through the end of the pipe, the projector lamphouses were being properly cooled.
Dan walked over to the first projector and, while looking through a set of smoked mirrors, he cautioned me not to look directly into the lamphouse. He flipped a switch on a small DC motor at the back of the projector, which began very slowly turning a set of sprockets and a worm drive. This was the mechanism that kept the positive carbon burning evenly across its end and fed it into the projector.
He then took hold of the arc-control knob on the side of the projector, and with the deftness of long-practiced skill, tapped the positive carbon against the negative, then gently withdrew it to the proper distance to strike and draw the arc. I still remember the noise it made; something like “PSSSSSHHHHeeeeeeooooooowwww,” and the ammeter in the control panel on the wall jumped from zero to 140. Dan looked up at the ammeter and adjusted the arc so it read 120, telling me that these carbons were rated for optimum burning at 120 amps. The control booth was now humming with the ringing sound of the DC arc, its furious blazing frequency determined by the dynamotor four stories below. We began to smell the barest whiff of burning carbon.
He ran a bit of the afternoon’s matinee as a test. The intermittents were beautiful pieces of intricate clockwork, each running as smoothly and quietly as a well-oiled (mechanical) sewing machine. I can still remember how beautiful the light from those arc lamps was, with the really gorgeous, lush color on the screen; and it does not in any way compare with today’s xenon lamps. Sure, they’re safer now and they can be run by kids, but this was when ‘Theatre Projectionist’ was a real profession and an art practiced by those who were proud to do so.
There was another aspect of the art of the job, one that involved an elaborate tap-dance that moviegoers never saw. I stayed through the matinee’, just to watch and appreciate Dan at work. The film on the first reel rolled smoothly through the intermittent, with just the hint of shutter noise. Dan, meanwhile, was threading the second reel on the second projector, striking the arc, and rolling the film to the sync mark at the beginning of the reel. Projector 2 stood in full readiness, poised to take its part in both the drama on the screen and in the dance in the projection booth. Near the end of the first reel, a bell, driven by the speed of the reel (it turns faster, the less film on it), began to ring. Well, it actually went, ‘ter-clank, ter-clank, ter-clank…’ Dan broke off our converation and took his place between the two projectors, watching the big screen through a glass. Without looking away from the screen, he reached out to each side, each hand deftly finding and grasping a knob on the end of a rod that protruded toward him from each of the intermittents.
At the top right of the picture appeared a flickering circle. This was the first of two changeover marks, and I saw Dan tense slightly. This first one was the ‘get ready’ mark, and five seconds later was the actual changeover mark. The second changeover mark flickered, and Dan swiftly, smoothly, and simultaneously pulled and twisted the knob from the right projector and pushed and twisted the knob from the left projector. The left intermittent snapped into life, and the scene change on the screen was absolutely, perfectly seamless. Meanwhile, the right projector was shuttered, its film running quietly out, while the left projector had taken over, its intermittent purring. ‘Wow,’ I remarked, impressed. Dan turned and grinned with pride. ‘And that, my friend, is how it’s done. Every reel, every movie, no matter how long.’
Dan liked this particular theatre, and also the smaller Chehalis Theatre, because of the type of projectors and the relative safety of the lower-power output from them. The Chehalis used smaller rods because the projectors had a shorter throw than the Fox. He sat in one night at the Drive-In and found he didn’t really care for the Drive-In units because the projectors there were many times the power, and the heat made everything touchy and erratic; those projectors handled essentially the same power as aircraft searchlights because of the tremendous throw required. They used xenon arc lamps, which are dangerous to handle. Inside the lamphouse they’re safe enough, because if one fails, the lamphouse contains the flying glass. But to change one requires a full face shield, heavy gloves, and a full leather apron to protect the person changing the lamp. If something went wrong at the drive-in it meant lots of horn-honking from outside, while you got things going again.