Any emulsion on standard celluloid shrinks and expands during developing. With a regular four-perforation image size, the shrinkage difficulties are largely controllable. In the double frame format (eight-perforation VistaVision), the shrinkage is a definite problem. Kodak Estar base was used to overcome this problem, as it is about three times more stable dimensionally than celluloid base. By using Estar we were able to have better stability over eight perforations than acetate would provide for a conventional 35mm frame.
High resolution over large image areas in one-to-one reproduction is a classic optics problem. A lens capable of resolving 160 lines/mm over a VistaVision format is roughly four times as difficult to construct as a lens for conventional 35mm. We researched all stock lenses and found that the 100mm f/2.8 RepNikor (lens #1) met our requirements. But this lens was only suitable for transferring an image from one projector into a printer camera. On an aerial image optical printer, or a printer with two projector heads, the transfer of an image from the film plane most distant from the optical camera necessitates both a second conventional copy lens (lens #2), and a "field lens." Positioned behind the first projector film plane, the field lens is required to bend the diverging light rays coming from the furthest film plane, through lens #2, into the Nikor (lens #1). Introducing a field lens cuts the performance of any lens dramatically, and to solve this problem, we designed a special lens which required no field lens, while reproducing an exceptional 180 lines/mm resolution, with no distortion. This meant that a blue screen shot could be placed in the first projector, and its matte in the second projector, so that as far as the camera was concerned, the two images were essentially the same. Result: improved matte fit.
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