Abstract: Security paper having a number of parallel lines having a substantially uniform first spacing, irregularly interrupted by a plurality of stripes having a second spacing greater than the first spacing, is flexographically printed on at least one face of a web which becomes, after further processing, a security document such as a bank check. The parallel lines typically are substantially straight and of substantially uniform thickness and formed of flexo ink, such as the type which becomes invisible when bleached. Alphanumeric indicia are preferably provided within the stripes either oriented parallel to the parallel lines (and alternately extending from top to bottom, and bottom to top), or perpendicular to the parallel lines. A pattern is provided that repeats at an interval significantly greater than the length of the security document formed from the security paper.

Abstract: An improved assembled pack or formset of credit card transaction slips with duplicating carbon slips having a series of perforations in the form of perforation strips aligned with the customer's credit card account number position on the transaction slips provided for the merchant, customer and credit card issuer. Simultaneous with deleaving or removing one of the transaction slips, the duplicating carbons are respectively split into two sections along the respective perforation strip, enabling the customer's account number to be accordingly split into two sections, and substantially preventing surreptitious reconstruction of the customer's account number from the used duplicating carbons.