Digimarc's product was a mark you could not see. The Oregon company hid digital watermarks inside photos, printed pages and video, small changes to the pixels or ink that software could read and people never noticed. A watermark could prove who owned an image or link a magazine ad to a website. Geoffrey Rhoads founded the company in 1995. It went public in December 1999, at the height of the dot-com rush.

Invisible Ink for the Digital Age

Rhoads incorporated Digimarc in Oregon on January 3, 1995, and built a pile of patents around one idea. Any picture could carry a hidden code that survived printing, copying and scanning. Photographers and stock-image libraries could track their work online. Publishers could let readers hold a printed page up to a webcam and jump to a website. Banks and governments wanted the same trick to fight counterfeit money and fake documents.

Split in Two, 2008

Digimarc priced its offering at $20 a share in December 1999 and listed on Nasdaq as DMRC. Over the next years its largest business became secure ID systems, such as driver's licenses. In 2008 L-1 Identity Solutions bought that business. Before the sale closed, Digimarc spun its watermarking unit off to shareholders as a new company on August 1, 2008. The new Digimarc kept the name and the DMRC ticker, and still trades on Nasdaq.

Cover: The Mill Pond, George Inness. Art Institute of Chicago, public domain. Chosen for a still mill pond (a watermark, hidden in plain sight).