Abstract: A process is disclosed for printing a document such as a negotiable instrument in a first and a second color for increasing the security of the document. A major portion of the document is printed with a first information in a first color from a first printer. A second information is created from at least a portion of the first information for proving a security pattern. The security pattern is printed over a minor portion of the document in the second color from a second printer to increase the security of the document. The process may be used for printing a check in a magnetically readable first color and a non-magnetically readable second color including colors having a color spectrum located outside of the color spectrum range of a conventional color photocopier.

Abstract: A target for ultrasonic camera comprising, applied to a substrate, a pyroelectric retina covered, in the present example, with a layer which absorbs incident ultrasonic waves; the temperature rise due to said absorption produces in the retina a charge relief read out by means which depend upon the selected device, for example an electron beam as in the case of the known pyroelectric targets.