Abstract: Documents bearing a thin reflective extruded security stripe comprising a leafing aluminum pigment having a gloss characteristic of from 20 to 24 as measured on a Gardner/BYK Microglass meter at a 60.degree. angle. A water soluble dye may be incorporated in the stripe. A method of making the document and a dye containing leafing aluminum pigment for extrusion on the document are also disclosed.

Abstract: A method of making a smudge-resistant thermally imageable document by applying a non-blocking ink stamp image receptive coating to the protective top coating, so that the image will dry within thirty second or less, and while producing an optical image density of at least 1.0. An ink comprising a dye, at least 8% m-pyrol by weight, a glycol, alcohol and water will dry quickly when applied from a stamp ink pad impregnated with that formulation.

Abstract: A method for altering a magnetic characteristic of a medium that includes the steps of providing a magnetic write head adjacent to a carrier bearing a fluid magnetic slurry, providing a sequence of randomly arranged information signals, and transmitting the sequence of randomly arranged information signals to a magnetic write head controller. The magnetic write head is operated in response to the controller to provide sequential representations of the randomly arranged information signals at predetermined amplitude levels in the fluid magnetic slurry by altering a magnetically discernible characteristic of the slurry. The fluid magnetic slurry is then cured to permanently fix the sequential representations.

Abstract: A randomly varying modulated current is generated and used to drive a magnetic write head in an apparatus for enhancing a randomly varying magnetic security characteristic of a medium. The write head can be positioned adjacent a fluid magnetic slurry for the purpose of altering the location of the various magnetic particles therein in a random fashion. The slurry can then be hardened thermally or using ultraviolet dryers. A circuit which can generate the randomly variable current for the read head includes a modulator which receives a first randomly variable signal and a second, different randomly varying signal which modulates the first signal.