Fragile water mark printed with two component inks and process

A method for authenticating printed documents comprises:

• a) obtaining at least one document having an image printed thereon comprised of at least two image segments of different feature size, said image printed with an ink for printing images which are visible both to viewing under white light and as fluorescent images when irradiated with ultraviolet light;
• b) illuminating both image segments with both white light and ultraviolet light;
• c) measuring a positive and negative contrast for both image segments;
• d) comparing the measured contrast values for the image segments to predetermined values;
• and
• e) based on the comparison, determining if the document is an original or if the document is identified as a copy.

An apparatus for testing a document printed with a security marking comprising:

• a) means for illuminating image segments of a document having two barcode segments;
• b) means for measuring a positive and negative contrast for both image segments;
• c) means for comparing the measured contrast values for the image segments to predetermined values;
• and
• d) means for, based on the comparison, determining if the document is an original or if it is identified as a copy.