A marking system that includes forming at least one marking in or on an
article, wherein the image formed is not visible to the unaided human
observer, and further contains at least one digital watermark. The
digitally watermarked image comprises emissive and photoabsorptive
portions. The digitally watermarked image is applied using a substance
reactive to a predetermined excitation source, and exposure to
ultraviolet light. Other traditional techniques, such as printing with
fluorescent inks may be used in combination. The digitally watermarked
image is subsequently observable upon exposure to the predetermined
excitation source. The digitally watermarked image may be observed and
decoded by appropriately configured detection systems, wherein the
information obtained may be used for purposes including, but not limited
to, authentication and security of the article or information contained
within the article.