Abstract: A cryogenic liquid, particularly liquid nitrogen, is used as a non-conductive fluid medium for freezing paper and as the liquid toner for electrostatic imaging. A web or sheet of paper is frozen using the cryogenic liquid to provide a dielectric surface for charged image areas to adhere to. The cryogenic liquid based toner carrier is particularly suitable for use in printing processes wherein a latent charge image is developed.

Abstract: Materials for printing information that are invisible under normal white or visible light but are x-ray opaque and ultraviolet fluorescent or absorbent are used for multiplex reading. The invention permits a reader to use x-ray radiation, ultraviolet light or visible light to read printed information. With the x-ray reading capability it is possible to read pages in sealed envelopes, thick documents or unopened attache cases.

Abstract: A fluorescent soundtrack readout system for decoding the digital soundtrack of a motion picture film employing ultraviolet light directed onto the surface of the soundtrack film to cause the digital indicia thereon to emit visible light and for transmitting the emitted visible light to a photodiode array to detect same.

Abstract: A motion picture film having a plurality of digitally coded soundtracks which are colorless and transparent to visible light and which fluoresce when exposed to ultraviolet light, unexposed film for providing the product, and the method for producing the product and methods for producing the exposed and unexposed films. The soundtrack images which overlie at least a portion of the visible image area of the film are digitally coded on the film using an electrostatic imaging system to imprint a fluorescent toner. The toner may comprise a fluorescent polymer having covalently bonded 3-phenyl-7-(amido or imido)-coumarin or certain substituted stilbene or N-alkyl-4-aminonaphalimides.

Abstract: A motion picture film having a plurality of digitally coded soundtracks which are colorless and transparent to visible light and which fluoresce when exposed to ultraviolet light, unexposed film for providing the product, and the method for producing the product and methods for producing the exposed and unexposed films. The soundtrack images which overlie at least a portion of the visible image area of the film are digitally coded on the film using an electrostatic imaging system to imprint a fluorescent toner. The toner may comprise a fluorescent polymer having covalently bonded 3-phenyl-7-(amido or imido)-coumarin or certain substituted stilbenes or N-alkyl-4-aminonaphalimides.