The Amazing Optical Adventures of Todd-AO |
This
article first appeared in ..in 70mm The 70mm Newsletter |
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| Written by: Jeff Hecht. Reprinted from Optics & Photonics News (Oct. 1996) by permission from the writer. | Issue 67 - March 2002 | ||||||||||||||||||
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As
impresario Mike Todd saw it, motion-picture technology was stagnant in
1952. Ticket sales had dropped with the advent of television. He needed
something new to pull in paying customers. Todd had just launched
Cinerama, a wide-screen system that put the audience in the middle of the
action. Yet he knew the cumbersome three-projector Cinerama system dated
from before World War II, and had split with his partners even before the
first Cinerama film opened. He wanted a better wide-screen system. The
night after
"This is Cinerama" opened in September [1952],
Todd asked his son to find "the Einstein of optics." |
Further in 70mm reading:
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The Professor and the Producer |
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Optical Design |
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| The
partners in Todd-AO brought an impressive skills to an ambitious task.
Todd was a master showman and promoter, quick to sense how to entertain
the public. O'Brien was an optical wizard, able to draw on other experts
at American Optical and Rochester. Todd's money only lasted a few months,
but he had sold Stewart so well that American Optical continued to support
the project. The developers faced tough challenges. They needed new
cameras, new projectors, a new film system, and special screens, and they
had to build them economically, and sell theaters on the new format. It
was a big project, and for a couple of years it kept most of American
Optical's new research division busy. One early decision was to use a large film format. Standard 35-millimeter movies looked dim when projected on the large screens of old theaters; larger film would show a brighter, sharper image on wide screens. Todd-AO settled on 65-millimeter wide negatives after locating old camera equipment that used that format, originally built for the obsolete Thomas Color process in the 1920s. Henry Cole supervised assembling and upgrading the camera mechanisms for use with the new Todd-AO optics, saving time and money. The new cameras shot frames five perforations high, in a 2.1 to 1 format. They could operate at the standard movie rate of 24 frames per second, or at 30 frames per second to reduce flicker, which is most noticeable on the sides of the screen. Recognizing the importance of sound, Todd-AO added six audio tracks, placed outside film perforations so projection prints were a full 70 millimeters wide. Cinerama used three separate cameras to shoot wide scenes; Todd-AO used only one. Because Todd wanted his films to tell stories, he needed lenses for everything from close-ups to panoramic shots. O'Brien decided on a family of four lenses, a giant "bug-eye" lens with 128 degree field, another wide-angle lens with 64 degree field, and two conventional lenses with 48 and 32 degree fields for close-ups. He farmed their design out to Robert E. Hopkins, an expert in fast, wide-angle lens design who had succeeded him as head of the Institute of Optics. The biggest challenge was the 128-degree "bug-eye," essential to film a wide image that would put the audience in the middle of the action. "That lens today is almost trivial to design, but it was not trivial when you had to do things on desk calculators," Hopkins recalls. His team punched countless numbers into Marchant electro-mechanical calculators, massive desktop machines full of wheels and gears that literally ground out results. They also turned to computers. Hopkins had earlier driven 90 miles to use machines at Cornell University, but for Todd-AO he made his first venture into remote computing, using the latest -- for 1953 -- technology. He installed a mechanical teletype in his bedroom to wire messages to an American Optical computer in Southbridge. However, the output did not go directly to the computer, a vacuum-tube behemoth with rotating drum memory that occupied a room 20 feet square. Another teletype in Southbridge printed Hopkins' messages for operators to code onto punched cards that the machine could read. Ray tracing was an elaborate procedure, recalls Richard Walters, a former American Optical engineer. One deck of cards contained the ray tracing program; separate decks described each optical surface. To trace a ray through the entire multi-element lens, they had to run the program deck, a surface deck, the program deck again, another surface deck, and so on until they went through all elements. To bend a lens, they had to punch a new deck for that surface, then run through the whole routine again. Because computer time was valuable, Walters says, "The fun was trying to keep it going all the time." The wide-field lens wound up a monster, with 12 spherical elements and two aspheric plates, including a massive 9 inch collecting lens that earned it the "bug-eye" name. Hopkins was pleased with his f/2 design and patented it. (Note 7) He recalls, "We probably didn't do more than 15 rays altogether. Today, you'd trace 15 rays for each image point. But I don't think they could double the quality of the lenses we designed." |
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A Suitably Dramatic Property |
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| "This
is Cinerama" became the third-highest grossing film in history,
(Note
8)
although it was little more than a series of clips demonstrating the
process. Todd wanted to offer more, a film of sweeping scope that would
shine in a wide-screen format. The hit stage musical Oklahoma! seemed a
natural, but Richard Rogers and Oscar Hammerstein II had refused earlier
movie offers. Todd changed their minds by demonstrating the Todd-AO
process, and by paying over a million dollars for movie rights. Todd hired Fred Zinnemann to direct the film. He used the big bug-eye for only a few wide-angle shots, including the opening shot through a field of corn and shots of a runaway buggy. He shot most outdoor scenes in Arizona, because Oklahoma itself was too cluttered with oil rigs and highways. The whole picture was filmed in both 65mm and standard 35mm formats to be on the safe side with so much money invested, helping run the filming budget to $4.5 million, a princely sum at the time. |
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The Problem of Projection |
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trickiest optical problems lay at the projection end. To put the audience
in the middle of the action, Todd wanted a screen 50 feet wide that was
flat in the center, but curved about 13 feet toward the audience at the
sides. Moreover, the one hole he wanted to project from was in a difficult
location -- the same projection booth used for standard films, which
looked down on the screen from an angle of up to 25 degrees. Like many ultra-wide angle lenses, the big bug-eye exhibited barrel distortion, making square objects bulge outward in the middle. One of the basic Todd-AO inventions was a compensation technique devised by O'Brien. He realized that projecting the image from the back of the theater through a conventional distortionless lens onto the deeply curved screen Todd wanted could largely correct for the inherent distortions of the camera lens. Nonetheless, some barrel distortion remained, causing vertical objects at the edge of the screen -- like telegraph poles -- to bend inward at top and bottom. Projecting from above onto a curved screen posed more problems: horizontal lines drooped in the middle with dish distortion, and keystone distortion made square objects look wider at the bottom. The degree of distortion depended on projection geometry, which differed among theaters. O'Brien decided to attack the problem by introducing compensating distortion in the projection print. Each frame on the film would be curved, but would look rectangular when projected on the screen. He assigned his son Brian O'Brien Jr., an optical engineer, and Siegmund to develop a projection printer that would warp the rectangular frames of the master negative into the shape needed in theaters. They planned two print formats to accommodate different projection geometries. It was here that troubles began to accumulate. The movie industry used intermittent projection printers, which exposed one frame at a time, for some special applications, such as titles, fading images, and lap dissolves. They normally made release prints by a contact process, speeding negative and film past a slit illuminated with diffuse light. Siegmund's group tried intermittent projection printing, but found it reduced image sharpness and contrast. They tried projecting the image onto bent film. Eventually Brian O'Brien Jr. suggested printing onto bent film in a continuously moving projection printer. To compensate for residual distortion, the imaging lenses had to be constantly oscillated back and forth from frame to frame. The resulting printer became quite complex. Siegmund recalls it had "three cams to drive the lens in three different modes, one to produce only keystone distortion, one for large barrel distortion plus keystone, and one for small barrel distortion plus keystone." Todd-AO designed three generations of printers, and built three copies of the fastest Mark 3 printer. The machine was still slow, and the color quality remained a concern. But a large and unpleasant surprise came when the original negative arrived to be copied at the Fort Lee, New Jersey plant of Consolidated Film Laboratories. The negative was covered with tiny scratches, and Siegmund found "every tiny scratch showed up in the projection print." The blemishes were not unique to "Oklahoma!" Editing and handling left them on all original negatives, but making fast-transfer contact prints with diffuse light washed out the imperfections. Projection printing just highlighted the flaws. The American Optical team hadn't known this; they were experts in optics, not in Hollywood practice. The young Todd-AO team tested a variety of new ideas. Coating the original negative with lacquer obscured some little abrasions, but not all. Unable to use ground glass diffusers because they would waste too much light, George Simpson adapted lenticular "bathroom" glass to avoid modulations on the film which might show up on the screen. "We reinvented every damn wheel in the process," recalls Siegmund. The pressure was on to finsh processing the film. Todd cranked up his publicity machine, and Life (Note 9) ran a long article featuring photos of Todd, O'Brien, the big bug-eye lens, and an "Oklahoma!" wagon train. The deadline was fast approaching for a premier performance at the Rivoli Theater on Broadway. Todd had contracted with Philips N.V. to build projectors in Eindhoven, and the Dutch company shipped the first 50 to him in New York just before the premiere. The problem was what would they show. |
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Screen Difficulties |
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| The
screen itself was also a problem. Concave screens are vulnerable to
cross-illumination, light scattering from the surface that reduces
contrast. Fred Waller avoided that problem in Cinerama by using a series
of slats about three inches wide, arranged like Venetian blinds, for the
curved sides of the screen. This blocked scattering, but it only worked
because the side projectors illuminated the slats from the sides. It
wouldn't work for a single projector, because each slat would cast a
shadow on the next, easily visible to viewers at the sides of the theater. Siegmund tried making a screen using an eschelle grating of lenticles, with step-like ridges along the curved sides to block scattering. That didn't work, but an American Optical metallurgist suggested adapting technology used to make wire frames for spectacles. "Dimpled" holes on a wire roller pressed bumps onto spectacle wire, and the wire in turn was wound onto a large embossing roll which could be rolled across the screen material to form a fine-ridged pattern. The idea almost worked, but slight imperfections left subtle patterns on the screen, and test screenings at the American Optical powerhouse showed that moving images made the screen pattern distractingly conspicuous. The final design for the Todd-AO screen came from Will Hicks, whom American Optical had hired to develop another of O'Brien's ideas, fiber-optic bundles for imaging. Hicks suggested using thin vertical ridges to block light from going sideways on a white screen, then went back to fibers. |
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Mixed Reviews |
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| Todd-AO
met the Rivoli deadline.
Reviewers extolled the musical, but complained about the print they saw at
the October 13, 1955 premier. In their last-minute rush, Siegmund's team
had problems with color correction; a color filter slipped out, leaving
one shot of Aunt Emma tinted magenta. However, the biggest complaints were
about the distressingly visible scratches highlighted by the projection
printer. That preview marked the end for the elaborate scheme of compensated printing. If Todd was bold, he was far from reckless. He had insisted on adding a second projection system to the Rivoli, so the film could be projected head-on from the mezzanine to the screen. Because the projector didn't look down, it could use contact prints made without correction, and Todd quickly shifted to those, which Siegmund says "were beautiful." Movie-goers and critics were delighted as well. The result was not exactly what Todd had wanted, but it worked well, and cost much less than Cinerama. "Oklahoma!" was a big box-office hit, and the energetic Todd moved on to produce "Around the World in 80 Days", a musical travelogue around an imaginary Victorian world based on the Jules Verne novel. In addition to striking wide-screen panoramas, it featured cameo appearances by actors including Buster Keaton. It won the 1956 Academy Award for Best Motion Picture. Veterans of Todd-AO recall it as intriguing adventure. Some, like Siegmund and O'Brien Jr., saw some scenes filmed. Many met Todd briefly, or encountered other entertainment personalities like Elizabeth Taylor or Agnes de Mille, the choreographer for "Oklahoma!". Todd called Hopkins about making a science film, and Hopkins asked him to "bring Liz" when he came to Rochester. That was not to be. Todd died soon afterwards in a 1958 plane crash, and with him gone, Todd-AO films faded away. American Optical lost money on the project. Hollywood eventually settled on a different wide-screen format, Cinemascope, originally developed by Henri Chrétien in 1927, which uses cylindrical optics to compress a wide image onto standard format film. The images may not match Todd-AO, but Cinemascope proved simpler and cheaper for theaters. The Philips projectors, designed to handle any 70- or 35-millimeter format, became highly successful, and some remain in use today. Todd-AO survived by concentrating on quality sound reproduction; its name still appears on movie credits. |
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Acknowledgements |
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| Thanks
to Robert E. Hopkins, Brian O'Brien Jr., Robert Shannon, Walter Siegmund,
Robert Tackaberry, and Dick Walters for sharing recollections and helping
with artwork. |
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About the Author |
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| Jeff
Hecht is Boston correspondent for the British weekly New Scientist,
contributing editor to Laser Focus World, and the author of books
including Understanding Lasers, Understanding Fiber Optics, Optics: Light
for a New Age, and The Laser Guidebook. He is not the author of Eugene
Hecht's widely used textbook Optics. |
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Notes |
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"Oklahoma!"
opening night at the Rivoli theatre, New York City. Image by Walter
Siegmund