Photo courtesy of Earl R. Gilbert and Local 728
Carbon arcs running on direct current were the state of the art in BFL technology when I first walked onto a film set back in 1977.* Although the first 4K HMI lamps had recently arrived in Hollywood from France, nothing could rival the output and quality of light produced by a carbon arc. It would be several years before reliable 12K HMIs were developed to challenge arcs, but most of the DPs I worked for -- as a juicer, Best Boy, and Gaffer -- preferred carbon arc lamps over HMIs all through the 1980's.**
A carbon arc is essentially a giant arc welder in a can with a glass lens in front. The sheet metal, rivets, and worm gear engineering of arcs has always reminded me of steam locomotives, and the advanced industrial-age technology envisioned by Jules Verne in novels like Twenty Thousand Leagues Under the Sea. You didn't just turn on an arc and walk away, but had to actually run the damned thing. There was an art to feathering the strike, adjusting the dancing electric flame through the little red safety-glass port, and "trimming" the arc -- removing the red-hot old carbons once they'd burned down to charred nubs and replacing them with fresh rods.
For another video clip demonstrating an arc in action, click here.
Plate on the side of each arc, demonstrating the proper gap between positive and negative carbons
Everything about arcs was big. Many of the classic Brute Arc "heavy-heads" were fitted with two folding handles on each side, one for each of the four juicers required to safely mount the lamp on an equally robust molevator stand. We could get away with using 2/0 cable when running just one arc, but powering two or more meant 4/0 -- at nearly a hundred pounds per hundred foot roll, the back-breaking bane of juicers the world over. When filming at the beach, we'd pull the wheels off each molevator, then mount it on a set of miniature tank tracks called "clickety-clacks" before heading-up the arc and tying the grid to the back two legs of the stand. The resulting rig looked like some kind of ray-guy weapon from a futuristic sci-fi movie, but clickety-clacks made our lives so much easier when working on sand.
Heavy-heads ran like a train so long as they were properly maintained and lubricated, but as the name implied, they were heavy, and a good sized crew was required to work with them. This wasn't an issue on big union features, but the commercials I worked on at the time had smaller crews, so we rented lightweight arc heads, which opened from the rear rather than the side. Along with running 4/0 from the genny, our morning ritual included lubing the worm gears that maintained the gap between positive and negative carbons with generous blend of kerosene and powdered graphite. For whatever reason -- improper maintenance, perhaps, exacerbated by the intense heat of a 225 ampere flame -- these lightweight arcs would sometimes run rough after hours of sustained use. I made a habit of opening the back of each arc between setups to allow the element to cool, and soon learned to carry spare arc elements on every job.***
Despite such issues, I really liked arcs, which could match daylight or tungsten lighting simply by switching carbons -- white for daylight, yellow for tungsten -- with no loss of light. Try that with an 18K HMI. An arc produces a very clean light requiring minimal color correction -- most of the time we'd add a frame of Y-1, a pale yellow gel, to bring the color temperature down to 5400 Kelvin without adding any reddish tint -- and unlike modern lamps using bulbs, the point-source of an arc throws a crisp, sharp shadow. Yes, they use a lot of power and thus are not nearly as efficient as modern lamps, but carbon arcs are cool, sexy beasts in ways no HMI or LED will ever be.
The first generation of modern arcs was the 170, which used 150 amps of D.C. power, after which the need for more light brought the Brute Arc into production, burning 225 amps. Mole Richardson eventually came out with the Titan, which reportedly consumed 350 amps, but I'm told they didn't catch on for a number of reasons. I never a saw a Titan arc on set or anywhere else.
In the early 80's, I worked a series of Murph 76 commercials shot on location in and around a Union 76 gas station at Dodger Stadium in Chavez Ravine. Most were daytime shoots using arcs as key and/or fill lights, but we did an all-nighter late one summer to shoot a Christmas spot using six arcs, each mounted on a set of two-high parallels. That meant six arc operators, one for each light. Once everything was rigged and ready for filming, I sat up there running my arc all night long.
With the gas station sprayed in a thick coat of soap bubble "snow," and bathed in cold blue light from our arcs, it was quite a sight. In the background, out of the camera's view, lay the dark outline of Dodger Stadium, silhouetted against the glittering lights of downtown LA. It was well after midnight by the time "Murph" (the gruff, crusty Richard Slattery) finally emerged from his motor home in a stuffed red Santa suit, then staggered around that sloppy mess barking his lines. The rumor on set was that he'd been hitting the bottle pretty hard that night, but who knows? All I do know is that once dawn broke, we had to pull those big, heavy arc heads and all-steel molevators down from the parallels, lug them to the truck, then wrap what felt like miles of dirty, wet, soapy 4/0 as the hot Indian Summer sun rose in the east, beating down on us like a sledge hammer. With our gloves, shirts, pants, and boots thoroughly soaked and utterly filthy, we then went our separate ways back home through the rush hour gridlock of LA traffic. It was an ugly end to one very long night.
With the gas station sprayed in a thick coat of soap bubble "snow," and bathed in cold blue light from our arcs, it was quite a sight. In the background, out of the camera's view, lay the dark outline of Dodger Stadium, silhouetted against the glittering lights of downtown LA. It was well after midnight by the time "Murph" (the gruff, crusty Richard Slattery) finally emerged from his motor home in a stuffed red Santa suit, then staggered around that sloppy mess barking his lines. The rumor on set was that he'd been hitting the bottle pretty hard that night, but who knows? All I do know is that once dawn broke, we had to pull those big, heavy arc heads and all-steel molevators down from the parallels, lug them to the truck, then wrap what felt like miles of dirty, wet, soapy 4/0 as the hot Indian Summer sun rose in the east, beating down on us like a sledge hammer. With our gloves, shirts, pants, and boots thoroughly soaked and utterly filthy, we then went our separate ways back home through the rush hour gridlock of LA traffic. It was an ugly end to one very long night.
Things changed when 12K HMIs finally became reliable. We still had to run plenty of cable, but once adjusted for a given shot, a 12K could be left alone until the next setup, with no delays to "trim" an arc -- remove the burned carbons and install fresh ones. The early LTM 12ks used 120 volt magnetic ballasts that weighed nearly three hundred pounds and were no fun at all to wrangle, but the advent of smaller, lighter ballasts powered by 208 volt (three phase) or 240 volt (single phase) A.C. brought the 12K HMIs into the mainstream of production. Still, we needed to carefully monitor the frequency of the generator, which had to remain between 59.75 and 60.25 hertz to avoid the dreaded "HMI flicker," which would cause the projected film to appear as though a demented camera assistant had been frantically opening and closing the iris during a shot. In the early days of HMIs, we'd rent a plug-in digital "freak-meter" to monitor the frequency on set, but when small hand-held optical meters became available, a Best Boy or Gaffer could accurately read the frequency simply by pointing the meter at the lens of a burning HMI. During my decade gaffing commercials, I always carried an optical freak-meter the size and weight of a pager on every job, but after a few years, flicker-free electronic ballasts came into use, turning my $400 dollar meter into a relic.
So it goes - the only constant is change.
18K HMIs eventually became the industry's go-to BFL, putting out more light than a 12K with no real penalty in weight. By the time 24Ks were introduced, I was working on multi-camera sitcoms that rarely left a sound stage, so I never had a chance to work with one of these mega-BFLs. My younger friends in Hollywood tell me that 24Ks have a relatively short bulb life, and suffered from lens-cracking issues early on, similar to those that plagued some of the first 12Ks. If a truly massive source of light is required nowadays, the 100K or 200K SoftSun units will do the job, but for most filming needs, standard 18Ks or the 18K Arrimax -- with no fresnel lens, essentially a giant PAR lamp putting out a lot of light -- seem to be the industry standard BFL for film and television.****
Although carbon arcs can still be rented in Hollywood, I hadn't heard of them being used in recent years except as props in movies about movies, but as you can see in this photo, there's a big feature currently in production using several arcs and shooting on 35 mm film. Terry Meadows at Cinepower and Light has a number of pristine Brute arcs in stock and ready to rent, so it seems the legendary carbon arc has come full circle from set lighting workhorse to show-horse and back again.
Arcs will still be rare -- you won't see them on many shoots -- but they're back in use, and if that's not a great Hollywood story, I don't know what is.
(Many thanks to Terry Meadows, Tommy Dangcil, and so many others on the 728 FB site who helped fill in the gaps of my arc knowledge.)
* Do I really have to explain what "BFL" stands for?
** Some of the early 12K bulbs had a tendency to explode like a bomb, with no warning at all. This scared the crap out of everyone nearby, and caused a delay while we cleaned out the head to install a new globe -- but sometimes the fresnel lens would shatter as well, which meant replacing the entire lamp. In a business where time=money, this was not good, and is one reason many DPs and Gaffers stuck with arcs long after 12K HMIs were introduced.
*** As this old post discussed, proper maintenance of carbon arcs was crucial.
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