Sorry Photo Engineer, that is wrong. The fluid is perchlorethylene, or dry cleaning fluid as most people call it, a solvent that is used because has relatively the same optical refractive index of acetate and is a pretty good degreaser.
Originally Posted by Photo Engineer
We use about 500 gallons of the stuff a year in our motion picture wetgate printers and in our Lipsner/Smith Mark IV ultrasonic cleaners.
Wet gate printing (for motion pictures) was developed by the Technicolor Corporation and has been refined over the years by others, but I have never heard of silicone oil being used as a wet gate agent...
Of course, the properties of noseoil are legend, right?
I don't know about the optical properties of silicone oil; it might possibly work in an optical printer, like an Oxberry or an Acme , but it would prove disastrous for continuous contact printing, where the oil would make contact with the element being exposed, which is the bulk of what we do.