How Things Get Invented

The history of motion pictures is an interesting one, and I am learning more about it in the context of my present work inventing stereoscopic motion picture systems, and in connection with the work I am doing with studios and filmmakers. I am taking working with filmmakers seriously because the quality of the Real D system is judged by the content projected on our screens. I was recently appointed as the co-chair (Peter Andersen is the other co-chair) of the sub-committee of the ASC Technology Committee tasked to help figure out workflow production pipeline and stereoscopic cinematographic issues. These subjects are tentative and need to be developed and we’re all learning together.

The stereoscopic cinema, in its present incarnation, as manufactured by Real D, is entirely dependent upon digital and computer technology. Digital projection allows for a single projector, while other stereoscopic systems use two projectors. Two projectors work well in IMAX theaters, based on my observations. I cannot say the same for theme parks, whether they use film or digital technology, because there are occasions when the projected image is out of adjustment.  

Replacing multiple machines with a single machine–i.e. a projector–is the way to go, especially in today’s projection booths; because typically there is no projectionist in the booth at the time the film is being projected. There is a technician who will assemble the film reels and make sure everything is going to project well, but then somebody else–maybe the kid at the candy counter–who actually works the projector and makes adjustments. (Interestingly the kid at the candy counter may be well qualified to work the servers and projectors because of his or her PC experience.) 

The product that I invented, the projection ZScreen®, has been used for years for the projection of CAD and similar images for industrial applications. Real D turned the ZScreen into a product that had to work even better for theatrical motion picture applications. It turns out that the film industry has very high standards when it comes to image quality. This is easy to understand, because the industry lives or die by image quality.  

The stereoscopic cinema has had a long gestation. To date, this is the longest gestation of any technology advance in the history of the cinema. For example, within about three decades of the invention of the cinema, sound was added. There were numerous efforts to make sound a part of the cinema and make it a bona fide product. In the three-year period from about 1927 to 1930, rapid advances were made both in sound technology and in aesthetics. If you take a look at movies that were made in 1927, and then you see movies that were made in 1930 or 1931, there’s a gigantic difference. Movies made in the early 1930s look a lot like, and sound like, modern movies. There was a tremendous advance in the technology and in filmmaker know-how in a short period of time. 

It is the creative professionals who will perfect the stereoscopic medium. That’s exactly what they did every time a new technology came along, whether it was sound, color, widescreen, or computer-generated images. In fact, those are the major additions to the cinema, and they all took decades to become an ongoing part of the cinema. Ads for movies never say, “This is a sound movie,” or “This is a color movie,” or “This movie is in the widescreen (or ‘scope) aspect ratio.”  It’s assumed. It’s a rare movie that is in black-and-white. It’s an even rarer movie that is silent. And nobody is going back to shooting 4:3 Edison aspect ratio movies. (Curiously, that’s more or less the aspect ratio used by IMAX for their cinema of immersion.)   

An attempt was made in the early 1980s to use a single projector with the above-and-below format–essentially two Techniscope frames that could be projected through mirrors or prisms or split lenses, optically superimposed on the screen, and polarized. The audience used polarizing glasses to view the images in 3-D. I was the chairman of the SMPTE working group that established the standards for the above-and-below format. But as soon as the standards were established, the above-and-below format was more or less abandoned. A few films like Comin’ At Ya! or Jaws 3-D, and one I worked on, Rottweiler: Dogs of Hell were projected above-and-below, an approach that was technically inadequate. For one thing it was hard to adjust properly and set up the projector to achieve even illumination. I know; I set up a few, and it was tough to do a good job because of the design of the lamp housings and the projectors.

Curiously it was the above-and-below format that led me to the first flicker-free stereoscopic field-sequential computer and television systems. I noticed that the above-and-below format was applicable to video, because that which is juxtaposed spatially can, with the injection of a synchronization pulse between the two frames, become juxtaposed temporally when played back on a CRT monitor; so the first StereoGraphics systems used the above-and-below format.  

The above-and-below video format, which is applicable to video or computer graphics, results in a field-sequential image that can be viewed using shuttering or related polarizing selection techniques. I design the first flicker-free field sequential system in 1980. It used early electro-optics that were clunky, but the flicker free principal was established. Using 60 Hz video, for example, with the above and below format, one achieved a 120 Hz result, that is to say, 60 fields per second per eye. The field sequential system is what is used for the Real D projection system. The electro-optics are different. There’s the ZScreen modulator used in the optical path in front of the projection lens, and audience members wear polarizing eyewear. (The combination of ZScreen and polarizing eyewear actually form a shutter. You can classify the system as either shuttering for selection or polarization, but in fact a proper classification is that it uses both polarization and shuttering.)  But the principal is the same as that used for the early stereo systems I developed. The right eye sees the right image while the left sees nothing and vice versa, ad infinitum, or as long as the machine is turned on. 

The issue I had to solve in 1980 was this:  How to make an innately 60 Hz device work twice as fast. And the above-and-below format did just that. We had to modify the monitors to run fast, but for a CRT monitored it wasn’t that hard. There are two parts to stereoscopic systems’ issues:  The selection device design and content creation. Today we are faced with the same design issue I was faced with in 1980. In addition, content creation has always been a major issue and that’s why I am working with the film industry to work out compositional and workflow issues.

(picture coming here)

Engineer Jim Stewart (left) and I are working on the first electronic stereoscopic field-sequential system that produced flicker free images (Circa 1980). We used two black and white NTSC TV cameras as shown, and combined the signals to play on a Conrac monitor, which, without modification, could run at 120 Hz. The images were half height, but we proved the principal. Stewart is wearing a pair of welder’s goggles in which we mounted PLZT (lead lanthanum zirconate titanate) electro-optical shutters we got from Motorola. The shutters had been designed for flash blindness goggles for pilots who dropped atomic bombs. I kid you not.


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