The system that we have now has twelve channels. You have your pan, tilt and roll. Then you have your track (for the camera) and your model track and, let's say, three functions for moving the model in X, Y and Z pitch, yaw and roll.
Most of the time you don't need all of those channels. Almost invariably you use pan and tilt; not always do you use roll; not always do you use boom, but you always use the track. I would say that we use five or six channels per shot, on the average. I've only had two or three shots where I've used all twelve channels. But they can come in handy when we have situations where we might want to motorize a lighting effect, or there is a miniaturized actor as a model that turns his head or lifts his shoulder or does something that takes the deadness out of the stick figure.
The new system will be modular. It will have four-channel components, so that you can add more axes in motion simply by adding more banks of computer cards. What we are really trying to do—as much as we are involved in equipment or "technolust:—is to make the system fun to use, so that the operators can exercise their ideas and add to the product in the most facile manner.
To execute the complex three-dimensional stop-motion animation in The Empire Strikes Back, we have Jon Berg and Phil Tippett. These are two animators who have knocked their heads against a wall for years and years and have really learned their art and they are truly adept men. I think they are the greatest and they have really done some marvelous stop-motion work on Empire, including quite a lot of pioneering in the art.
I've already talked a lot about our main tool, which is motion control photography and which allows us to repeat identically the same move once it has been programmed. The other major tool that goes hand-in-hand with that is the blue-screen process.
I had considerable experience with the blue screen process during the years of 1963 through 1967 when I was working with Joseph Westheimer, ASC, who was my mentor in the business. I was a photographer prior to that and, through his good offices, I worked with him for four years and learned a great deal about special effects. We started working out the early problems of blue screen while I was associated with him.
I became extremely enamored of the process, because it enables one to extract a perfectly-fitting matte from the same negative that the image is on. There are many ways of doing blue screen, and every self-respecting optical house has its own blue screen technique. They are all somewhat different. Some of them work well and some of them work in certain circumstances and not in others. Some don't work at all.
I remember when I first suggested to George Lucas that we shoot all the Star Wars material in England by means of blue screen, rather than front-projection. I knew I was really sticking my neck out, because there is nothing that makes a director more paranoid than going to dailies and seeing all of his perfectly timed and matched action with a blue background that, by itself, is totally useless. He is, thereby, putting himself completely in the hands of the person who is going to do the special effects for him. Since, at that time, we hadn't had any experience with him, and we were learning also, it was rather tenuous. But we wound up doing it that way, since the front-projection techniques didn't work out to be logistically possible.
We worked out a system of doing blue screen on Star Wars and it was adequate for the type of work we were doing at the time, which was mainly spaceships over star backgrounds. In deep space you have a lot of license that you can take because nobody has ever been there and we don't really know what it looks like. Besides, all you have to do is matte out stars to keep them from going over an object and do it so that the matte lines won't show.
There are some perfect matte shots in Star Wars. The system that we worked out in the meantime is based on a continuous tone film as the matting stock, rather than high-contrast at all in the matting process, except for garbage mattes or something like that. The thing is that the edge quality of high-contrast film is so different from that of color negative that you wind up clipping the matte lines and clipping the edges of the film. That works out pretty well in a shot that moves along (if you have a one-second cut you may not notice it), but if you get into a shot that plays for any length of time on the screen, it doesn't work when it slows down past a certain point. So we've developed the system now so that we are able to achieve perfectly believable matte shots in most cases, and we would, I think, be able to do it in all cases if we had as much time as we'd love to have.
The blue screen process is dependent upon good photographic technique, probably more so than it is on the printer that you work with. But the general optical systems that are available and are designed basically for the workhorse types of opticals (fades, dissolves, reductions, flops and the various blow-ups for getting rid of the mike booms)—that type of printer is not acceptable for composite photography, if you are doing a great amount of it.
Consequently, we designed a printer for composite photography that has a couple of basic differences from the standard optical printer. We were able to design a printer for doing blue screen work and it has the finest possible optics that could be achieved within the time frame. In fact, even if we had had more time, I don't think we could have gotten a better lens.
We designed what is actually a four-headed, optical, beam-splitter printer. It takes two pairs of VistaVision projectors, each pair with a relay lens that is distortion-free between it and an anamorph that then takes the VistaVision image and reduces it to a 2-to-1 anamorphic ratio suitable to intercut with the film which we shot in Panavision. This lens has exceeded our expectations. In about 30 to 40 percent of the shots we have actually had to degrade the image in order to make it look real. It looks too crisp in certain cases and we have been in a position of degrading the image to make it fit, rather than degrading the background to make the image work with it. So I think we've achieved a marked degree of success with our new printer and the results will show on the screen.
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