IMAX projectionist one of a rare breed

AUSTIN (KXAN) - Most of us have experienced it at one time or another: We pay good money at the door of a movie theatre, plop down in our seats with our popcorn and soda pop and train our eyes on the screen. The movie starts and then, just as quickly stops.

Best case scenario: A quick repair restarts the projector and the moans and boos quiet down.

Worst case scenario: The film gets stuck in the projector and the lamp burns a massive hole in the celluloid. Time drags on; the audience grows restless. The poor kid in the projection booth starts crying. Life on Earth as we know it comes to a devastating end.

Now, take all that and ratchet things up some 10 billion times and you get some sense of what life is like inside the projection booth of an IMAX motion picture theatre , especially when the movie is a 3-D blockbuster that fans have been waiting to see their entire lives.

Welcome to Pat Caldwell's world.

"No one knows I exist if everything goes well, but let the least little thing go wrong and all eyes turn to the booth," said Caldwell, the chief projectionist at the Bob Bullock Museum of Texas History's IMAX theatre.

Take the time a few months back when the latest 3-D film hit the theatre. A crowd of invited guests filled the auditorium as the lights dimmed and the movie started. Staring through their 3-D glasses, members of the audience were startled by a fuzzy, out-of-focus screen featuring strange colors and patterns. Heads turned; moans emanated from disappointed patrons. Panic knocked on the door of the projection booth.

"What happened was we went to a different set of polarizers," Caldwell said. "We were using 90-degree polarizers with the projector and 90-degree glasses to match. We decided to go to 45-degree polarizers because they polarize better. What happened was they didn't give you the 45-degree glasses; they gave you the 90-degree glasses. That problem has been eliminated."

The IMAX beast, though, has multiple heads. It's kind of like a golf swing: There are a thousand things that go wrong and any one of them can produce decidedly unhappy results.

"It runs off of electricity," Caldwell said. "It also runs off of compressed air; I have a big industrial air compressor that supplies air at 120 pounds per square inch to the projector.

"There's also a circulating coolant that runs through the two xenon lamps that reach the temperature of the sun. So we don't want things melting, especially the film. So there's circulating water cooling the lamps and mirrors.

"Then there's the proprietary software that IMAX has for the sound computer," he explained. "It's running Windows NT system with an 'Oh, my heavens' 400 megahertz processor. I don't even think the Smithsonian would want it now. So you have to play computer programmer.

"I have a laptop running slides; it's programmed in DOS. I'm probably the last person in Austin that daily programs in DOS. So it's a big combination of odd skills. Plus you have to be willing to sit in the dark in a noisy room, can't leave, for eight hours a day. That's part of the contract with IMAX. Once that equipment is running, you stay in the projection room. The equipment is valued at about $5 million, so it behooves us to keep someone there to maintain an eye on everything," Caldwell explained.

Oh, yeah, there's also the tape bubble thing. You see, an IMAX movie in the box is huge. It's also heavy. In fact, it is so huge and heavy it comes not in one box, but many. An IMAX 3-D movie is twice as big, because it contains separate reels for the right and left eyes.

For example, Tron: Legacy, the 3-D sequel to the classic 1982 Tron , arrived at the Bullock this week in 76 boxes. Altogether, the 18 miles of film inside them weighed out at 1,100 pounds. It was Caldwell's job to splice each piece of film together onto two six-foot diameter reels to feed into a projector that fills an entire mid-size room. Each end of each piece of film had to be trimmed in a zigzag cut, fit together in order, with each edit point securely taped and sealed.

"It's critical that there be no bubbles in the tape," he said. "The film moves so quickly through the projector that any defects in the splice might cause it to come apart and IMAX film costs about $200 per minute. So we don't want any errors. It's an especially formulated tape; it's formulated to stick to the film. It sticks like crazy to film which is what you want. You do not want splices coming apart when you have film running at 337 1/2 feet a minute."

As you can imagine, people with Caldwell's combined skill set are few and far between. There are less than 200 IMAX chief projectionists worldwide and almost all of them are just that: projectionists.

Caldwell, though is also a certified IMAX technician who once hop-scotched around the planet, trouble-shooting problems and making repairs to the multi-million dollar machines. He was a virtual one-man SWAT team, beaming down to tackle emergencies.

"When I was an IMAX tech, I had one in